You could definitely get a pretty sizeable gain from porting the stock heads but an aftermarket will almost always out perform them they’re simply just designed better
I love the BBC stuff. Over the years on my Chevelle I have run stock ovals and stock rec ports on a 454. I thought the rec ports would make a huge difference but I am not as impressed as I expected. My combo is mild by most standards. With all the money it takes to rebuild a set of factory heads I believe I would have been better off with a set of aftermarket aluminum ovals. My opinion.
Even if you install good undercut valves with a extra 15 degree cut on the intake valves and cleaning up the bowls and short side radius then installing good valves on the exhaust along with epoxying the exhaust floor raising it 3/8 and blending it into the bottom angle of the seat to help the exhaust short side, it will definitely help a lot. The exhaust port is way to large and the tight radius on the short side really hurts the exhaust flow. I think it will pick up a good amount but it can’t come close to the AFR’s ports and valve location, valves and seats. That’s my thinking.
Mark Jones at VortecPro gets great results out of his ported iron heads. 570hp pump gas 467ci with 236 peanut ports, 620hp with 049 oval ports, 680hp when stroked to 496ci and 720hp on race gas with a solid roller.
@@andysteele4056 and he got that performance at elevation if I remember correctly which is even more impressive However…..he’s got a tricked out transmission so keep that in mind
I have built a lot of big block Chevy's for drag boat racing. Iron heads are the way to go for anything marine. lake and sea water used for cooling a boat engine a killer of aluminum heads, unless you have the water jackets coated with a ceramic. however, then you lose some of the cooling benefits of aluminum. so iron is the way to go for power boats. My favorite factory casting is the rectangle port head, casting number 3994025. it is the 71 LS6 corvette head. They are ridiculously rare with only around 200 pairs made, and what ever service replacements they made. it is basically an open chamber version of the 3964291 L78\L72\L71\LS6 head, which is my second choice. they made a ton of these. basically, the only difference between them is the chamber. but the 71 heads flow better because of the open chamber. but you need either a big CID motor, or high dome piston to take advantage of them. even then, they do not flow as well as aftermarket iron heads. I think the only 2 companies still making iron heads, are GM and World Products or if you can find them used, the old Dart Iron Eagles. which were basically a copy of the old 71 454 LS6 corvette head, but with raised exhaust ports. I first choice for anything marine is always aluminum with ceramic coated water jackets, followed by iron heads if it is a budget Marine Motor. my personal favorite head for most budget marine motors, is the 71 3993820 oval port head, and 72 3999241 heads used on the LS-3 396/402 and LS5 454. cut them for bigger valves, and some minor port and chamber work and they will out flow pretty much any Iron big block head. and the torque down low is amazing.
Good comparison, I would love to see a set of aluminum rec ports compared around the size of a 290-315 cfm with these iron heads…. Keep it apples to apples. The oval ports surprised me a bit, but intake mismatch will be an issue with a single plane intake.
On my 509 bbc I had a set of pocket ported 188 casting rect port heads and a solid roller cam, comp cams std grind @ about 740 lift. Made 690hp. Switched to a set of AFR 305 and fully ported 4500 intake, both by Eric Weingartner. Made 818 hp. Those iron heads can be improved upon, but I don't think you can match the performance of the better aluminum heads. Especially in the hands of a porting pro.
What was the CR on that 509cid? Running a 730 lift cam on 540 with iron heads. Just wondering what I’m leaving on table by not going aluminum Brodix or similar.
I haven't done it myself, but I think the iron stock heads can be modified enough to match the aftermarket iron heads. However then the question is cost. How much would it cost to get stock heads up to the same as aftermarket performance and setup the value springs to match the cam, vs aftermarket heads out of the box specs tailored for your engine. Now this entirely my opinion but I don't think that iron heads could ever be made to out preform aluminum heads due to the increased heat and detonation limits of iron heads. I think aluminum allows for better cooling and give a little more range from detonation to use more aggressive timing. What I like about the aftermarket heads is you can order them with what you need or they are set up for your cam specs for your cam you are using to prevent valve float. I know cost wise the aluminum tends to be more expensive, but the price is close enough I wouldn't use iron heads or buy aftermarket iron heads unless I had too. For example qualifying for a specific pure stock class. For a 300 bucks or so more I'd rather have aluminum heads for better tuning and drivability. If on limited budget I used stock heads unless there's some problem that causes the heads to need replacement.
I was watching a real where they dimpled a head port. It created quite the argument over whether it would improve performance. The theory of it being similar to a golf ball increasing velocity, while others predict that it increases atomization. I think it would be interesting if you could see if there’s any validity to these theories. Thanks for the content!
I would love to see the 496 with the AFR heads with a big drag cam!! 278-282@50 and 750 plus lift! let's see what that 496 makes then!! I'll bet It makes 775-800 HP!! Bring on the bad boy cam Richard!! PLEASE!!
I've been looking into this alot, since I've got a set of 188 rec port heads (same as your 088 essentially). I've been on the fence between using these or a set of 781 heads on a 427 I'm building. It seems like to me, the real weakness of the factory rec port heads is the exhaust port. The intake ports flow alright stock, around 300cfm or a bit more, but the exhaust port is weak and only flows around 60-65% of the intake, when it should ideally be closer to 75-80%. I'm pretty sure this is the reason GM used such a huge split between intake and exhaust duration on the square port crate engines like the old 454HO. They used the cam to compensate for the poor exhaust port. I think with a basic 60 grit casting cleanup on the intake ports and some minor work on the bowls and shrink the guide bosses, then do the same on the exhaust and also give a better radius on the short turn and open up the throats, I think there are very significant gains to be made with the factory heads.
I gotta set , my 1971 026 castings square port heads. 572 big block 850lift cam 15/1 compression make 810hp. I don't know what the Afr 377/385 heads 950-1000 hp. Send me afr 385 and I will see.😎
I could make you that power with the #781 #049 casting heads but i I have a magazine quoted figure of 650hp with factory GM iron rec port open chamber heads 2.19" in 1.88" exh on a 509ci 4" stroke 4.5" bore chev with the comp cams magnum solid roller. If I remember rightly it had a out of the box Weiand intake, on #7535 and 1000cfm 4150 flange Holley carb. And made in the 800hp region with nitrous. 9second quarter mile combo.
Yes you can but should you? If not restricted by rules I'd say don't try to make irons outperform aftermarket aluminums. There's a 2013 Yellow Bullet thread with Chad Speier worked 088s that I guess made 841hp na in a high cr truck pull application. 2.3 valve, epoxy, 374/385 cfm ar 1". Can be done, not sure if he's will to do the iron stuff anymore but for the price/time I'd start with something else unless I was boxed in via rules. He's gotta video on them too about a year back. Nothing wrong with a basic port job if that's what you got but to make them great takes a lot of effort. Buying a bare set of promaxx as cast and porting yourself, parting yourself/machining at a machine shop that does race engines/heads... might be the more budget friendly way to go.
I think you can maybe matchbthe summit but remember both aftermarket heads are probably running raised exhaust ports with help the flow number quit a bit. Factory to AFR, i highly dought it could be done. Would have more money if the stock heads then just buying the AFRs. My 2 cents.
I was going to say which someone brought up that you already have dyno results for professionally ported 781 ovals. I’d say yes to porting the rectangular. 496 might like an even bigger port also.
Rich we had ported sqare port heads off of a 427 vett engine I forget what year they were the car we had these on had a tunnel ram and a solid roller cam 700 lift we switched to a pair of brodax heads after milling and a good valve job we only picked up 1 tenth of a second these were on a standard bore 454 we were upset because we spent all of that money with so little gain and to show how good the factory heads ran this 1968 camaro ran 8.90s on motor in the quarter mile and 7.90s with a 225 shot of nitrous at a 170 mph this is going back 25 years ago, hope this gives someone an idea showing what factory heads can do compared to aftermarket with a time slip instead of a dyno number
Were you running a automatic transmission or standard transmission? I have a 68 Camaro with a 4 speed muncie m22 in it. It has a built 355 small block but I'm looking to go to a big block as I can't seem to get the torque need to have the power it had with the close ratio transmission it previously had. I literally could get rubber in all 4 gears. Now it is limited to 1st and 2nd, with a slight bump in 3rd gear.
@jsharp7260 you had different ratios in the previous transmission that's one thing. Instead of putting a heavy BBC in your car, take your small block and stroke it to 383 ci. with a Scat 9000 3.75" stroker kit. Be a lot less expensive plus with the right camshaft and tuning you'll be over 500 ft/lbs of torque.
@@hoost3056 Thanks for your advice on this. I do have some extra things that I wouldn't have to pay for such as machining and I have some big block things already. So it might not be to far off. I'm going to be looking into a forged crank for this build as well. So we'll have to see what becomes of this. Maybe in the future I will post my results on here.
Most never explore what the factory heads can do. You had great results with your 454 factory head camaro........there's guys out there that won't run those numbers with all the "best" parts in a 540 bbc. I much prefer good factory headed combos
What do we have to do to get someone to compete with raylar on the 8.1l heads? Raylar customers all complain about their after sale treatment, and they screwd up the valve alinement on LT's "ugly truck 2.0". At what point did America allow for monopolized flip you over a barrel costs, with no support? 4000$ for aluminum heads is twice the price most other heads cost. Even summit fails the L18 headbolt pattern in support. The vortec8100 basically can't blow head gaskets, it cracks pistons first. The stock heads weigh more than I do lolol, and flow less then the 5.3l. Frankly I'd have thought someone would have matched the ls7 intakes to the 8.1l block with an aluminum head when the block was moved into the purely aftermarket in 2007/2009.
No experience with Rectangular port iron heads, but lots with large ovals. 781 heads can see big improvements from porting, on my engine to the tune of 632 lb/ft at 3200 solid cam single plane, 13:5/1 comp. 468 c.i. I doubt they'd touch anything made by AFR though.
,,, well, still wondering for about 53 years, port for port, valve for valve, chamber for chamber, all equal, ,,, is the iron worth how much with the less thermal conductivity ,,, ?
No most stock heads will start cracking at the port volumes required to get that much horsepower Ask me how I know, I have a set of junk max ported iron heads. The short side of the port is awful Go with aftermarket heads and save your money
Richard. Love the videos. Do you have a video showing how a Gen VI 454 big block performs with an eBay turbo kit? Stock heads, stock cam is what I’m looking for.
489 bbc 9.8 cr ported 990 rec port , preformer rpm air gap , 232 236 @.050 about .600 lift. made 624 hp 640 tq with a 850 elderbrock , 640hp 670tq with a 950 holley
I myself have a vortec 454 gen 6 and would love to get the AFR heads, but I am curious to know what the 279 heads would do with porting. How would they compare to the summit heads? Is that something that could be done in the future? Looking for all the torque for towing!!
You'd certainly pick up some nice gains by porting the stock rectangle ports, but IMO you're not going to make up this much difference. Plus, by the time you spend all that money to get it done, you could have bought the AFR's.
Richard This all depends on cost - AFR Aluminum heads cost $3500.00 partially CNC Summit only shows aluminum heads @ $820.00 ea. complete no more cast iron heads available So I'm in the head business I run BBC Iron Heads on my own engine = WHY because I already had the heads and I don't charge myself for the work --- LOL OK - There is no one in the country CNC porting iron heads it is way to detrimental to the machines and water soluble oil is not the best product to use on cast iron so a coolant change @ 50 gallons??? Now you're at hand porting - not fun - and time consuming - I charge more if the customer want iron heads ported - getting the two ports to flow the same or close - good luck with that on GM heads but it is possible to get them close with a lot of flow bench time - yuck - the heads weight 65-lbs each bare, and lift them up on the flow bench - OK (superflow 600 serial #001) Now they're ported, we have to fix the valve guides, cuz who wants to run 3/8s valves - LOL --- Where do you want to go here 11/32 or 5/16s - liners are ok for the EXH - but to do a good job on the intake you have to knock the guides out - AND - you can't put the factory guides back in because they drill the guides after they put them in the heads, so replacement guides, I use PEP bronze guides for that, you can get them in either 11/32 or 5/16. That done lets cut the seats on the SERDI Machine and cut the guides for seals, springs and be sure the spring height works for the springs the cam requires - What CC's do you want in the chambers, cuz you can only cut the heads so far until you run into the intake valve seat, WHY well by the time you get the chamber to flow correctly it CC's out at about 135, you can angle mill um about .125 off angle but then you have to fix the intake manifold side and all the bolt holes (@ about 400 bucks extra) If'n you already own the square port heads this is going to cost you (less the freight) about $3400 bucks $3900.00 if you get um angle milled - then how much did the valve-train parts cost you and the valves? - Which are not included in that price OK - Great - Here's the catch 22 on this --- if the iron heads flow close and the valve size is the same and the compression is the same the iron heads will make more power, then the aluminum heads, so the only savings you get is the weight differential, to get your power back you have to raise the compression 2 points ---- If you have to run PUMP-GAS you are stuck with about 9 to 10 to 1 and hope it doesn't detonate the rings out of the engine -- OH OK lets pull some timing out of the motor - LOL - You're better off with a bit less compression and give the engine what it needs for timing THAT'S MY 2 CENTS WORTH So I found this At Summit a World Products CNC Iron SQUARE PORT HEADS www.summitracing.com/parts/wrl-030620cnc/make/chevrolet
Richard, are there any aftermarket street aluminum heads that will work good with flat tops...454? Seems all aluminum heads can only get with overly huge ports. I would like a step above the peanut ports. Not sure why manufacturers have not caught on to this yet. A small chamber but much better flowing than 236 and matching high rise intake
@@richardholdener1727 I just watched the hunt for grunt videos - thanks! I'm building a 5700lb 68 Impala and the videos really helped point me in the right direction.
Question for you unrelated to the heads: Was this comparison done on a stock GM block? 2 or 4 bolt? If 2-bolt, are you comfortable with stroking it and making these power levels reliably for a street car?
I've always wanted to see a test where you trade off head for cam - i.e. it takes that 300 roller to get to 630 hp on that BBC with stock heads, how much smaller/more streetable a cam could you run with the AFR's and still hit that 630 hp performance level? I also wish these published tests would record idle speed and idle vacuum values so readers could decide if they could live with the street manners of a given cam, if they could run power brakes, and so-forth.
Could be right, hard to say (these 290s vs same flow bench/same dyno/same day). Can't really compare different flow benches with AFR advertised vs people that sell 088 truck pull stuff so 🤷♂️ Can make em pretty good though. Even though it's totally apples to oranges with different benches and maybe different methods (inlet radius...) Speier's 088s seem comparable to the AFR 290 and look like the outpace it on the upper end. Apples to oranges, dunno
Hey Richard I apologize if you ran this test on a video already but I want to know is it worth putting a tunnel ram on a almost bone stock gen 6 454, what would be the HP/torque with stock heads and cam ECT ?
I have a 489 with a roller sets up and a 525 ish cam and 781 ported heads . How much more power would I gain with a set of aftermarket heads. compression is about 10 to 1. on pump gas and a 850 carb?
Can we please stop using these strokers for these test. Most guys just have a .30 over 454 or maybe a 402. These just don't apply to the average guys power plant.
Did you listen to anything he said? It's not about the motor the heads are on, he's showing us differences between the head options. You can apply this information to any big block...
Yeah the strokers are only used to tax the heads more and show the differences better. You can figure it out mathematically by dividing the HP/TQ by 496 then multiply the result by 468 for the .030 over 454. That will give you a rough idea.
@@DBSSTEELER numerical theory is far different than real world. You can extrapolate though you will have far too many variables for accuracy in prediction.
I believe Mark Jones routinely makes over 700 hp with ported factory OVAL PORT heads on pump gas on a 489.
Most of his builds are about 650 hp
You could definitely get a pretty sizeable gain from porting the stock heads but an aftermarket will almost always out perform them they’re simply just designed better
I love the BBC stuff. Over the years on my Chevelle I have run stock ovals and stock rec ports on a 454. I thought the rec ports would make a huge difference but I am not as impressed as I expected. My combo is mild by most standards. With all the money it takes to rebuild a set of factory heads I believe I would have been better off with a set of aftermarket aluminum ovals. My opinion.
Even if you install good undercut valves with a extra 15 degree cut on the intake valves and cleaning up the bowls and short side radius then installing good valves on the exhaust along with epoxying the exhaust floor raising it 3/8 and blending it into the bottom angle of the seat to help the exhaust short side, it will definitely help a lot. The exhaust port is way to large and the tight radius on the short side really hurts the exhaust flow. I think it will pick up a good amount but it can’t come close to the AFR’s ports and valve location, valves and seats. That’s my thinking.
Needs chamber mods on the exhaust side also it’s in vizard big block book
Mark Jones at VortecPro gets great results out of his ported iron heads. 570hp pump gas 467ci with 236 peanut ports, 620hp with 049 oval ports, 680hp when stroked to 496ci and 720hp on race gas with a solid roller.
His Chrvelle can run a mid 10 with the peanut port heads he does with like a 238 @ .050 hydraulic ft cam and 9.5:1 compression.
@@andysteele4056 and he got that performance at elevation if I remember correctly which is even more impressive
However…..he’s got a tricked out transmission so keep that in mind
@@zachmartinez-lg7jj yes, in pueblo, co at 4,000 ish feet. trans is a th350 with 3500 stall.
@@zachmartinez-lg7jj But MPH is MPH. That's a result purely of HP. His motor is legit.
I have built a lot of big block Chevy's for drag boat racing. Iron heads are the way to go for anything marine. lake and sea water used for cooling a boat engine a killer of aluminum heads, unless you have the water jackets coated with a ceramic. however, then you lose some of the cooling benefits of aluminum. so iron is the way to go for power boats. My favorite factory casting is the rectangle port head, casting number 3994025. it is the 71 LS6 corvette head. They are ridiculously rare with only around 200 pairs made, and what ever service replacements they made. it is basically an open chamber version of the 3964291 L78\L72\L71\LS6 head, which is my second choice. they made a ton of these. basically, the only difference between them is the chamber. but the 71 heads flow better because of the open chamber. but you need either a big CID motor, or high dome piston to take advantage of them. even then, they do not flow as well as aftermarket iron heads. I think the only 2 companies still making iron heads, are GM and World Products or if you can find them used, the old Dart Iron Eagles. which were basically a copy of the old 71 454 LS6 corvette head, but with raised exhaust ports. I first choice for anything marine is always aluminum with ceramic coated water jackets, followed by iron heads if it is a budget Marine Motor. my personal favorite head for most budget marine motors, is the 71 3993820 oval port head, and 72 3999241 heads used on the LS-3 396/402 and LS5 454. cut them for bigger valves, and some minor port and chamber work and they will out flow pretty much any Iron big block head. and the torque down low is amazing.
Aftermarket heads will always have the upper hand as water galleries and port shapes are optimised to give maximum effort straight up.
Good comparison, I would love to see a set of aluminum rec ports compared around the size of a 290-315 cfm with these iron heads…. Keep it apples to apples. The oval ports surprised me a bit, but intake mismatch will be an issue with a single plane intake.
On my 509 bbc I had a set of pocket ported 188 casting rect port heads and a solid roller cam, comp cams std grind @ about 740 lift. Made 690hp. Switched to a set of AFR 305 and fully ported 4500 intake, both by Eric Weingartner. Made 818 hp. Those iron heads can be improved upon, but I don't think you can match the performance of the better aluminum heads. Especially in the hands of a porting pro.
What was the CR on that 509cid?
Running a 730 lift cam on 540 with iron heads. Just wondering what I’m leaving on table by not going aluminum Brodix or similar.
@@wallywire 12:1
I haven't done it myself, but I think the iron stock heads can be modified enough to match the aftermarket iron heads. However then the question is cost. How much would it cost to get stock heads up to the same as aftermarket performance and setup the value springs to match the cam, vs aftermarket heads out of the box specs tailored for your engine. Now this entirely my opinion but I don't think that iron heads could ever be made to out preform aluminum heads due to the increased heat and detonation limits of iron heads. I think aluminum allows for better cooling and give a little more range from detonation to use more aggressive timing. What I like about the aftermarket heads is you can order them with what you need or they are set up for your cam specs for your cam you are using to prevent valve float. I know cost wise the aluminum tends to be more expensive, but the price is close enough I wouldn't use iron heads or buy aftermarket iron heads unless I had too. For example qualifying for a specific pure stock class. For a 300 bucks or so more I'd rather have aluminum heads for better tuning and drivability. If on limited budget I used stock heads unless there's some problem that causes the heads to need replacement.
David Vizard could get close on those factory rec ports.
So could Mark Jones.
I was watching a real where they dimpled a head port. It created quite the argument over whether it would improve performance. The theory of it being similar to a golf ball increasing velocity, while others predict that it increases atomization. I think it would be interesting if you could see if there’s any validity to these theories. Thanks for the content!
I would love to see the 496 with the AFR heads with a big drag cam!! 278-282@50 and 750 plus lift! let's see what that 496 makes then!! I'll bet It makes 775-800 HP!! Bring on the bad boy cam Richard!! PLEASE!!
I would like to see this test with an actually Chevy BBC 427 and a 454 made for high HP.
I've been looking into this alot, since I've got a set of 188 rec port heads (same as your 088 essentially). I've been on the fence between using these or a set of 781 heads on a 427 I'm building. It seems like to me, the real weakness of the factory rec port heads is the exhaust port. The intake ports flow alright stock, around 300cfm or a bit more, but the exhaust port is weak and only flows around 60-65% of the intake, when it should ideally be closer to 75-80%. I'm pretty sure this is the reason GM used such a huge split between intake and exhaust duration on the square port crate engines like the old 454HO. They used the cam to compensate for the poor exhaust port. I think with a basic 60 grit casting cleanup on the intake ports and some minor work on the bowls and shrink the guide bosses, then do the same on the exhaust and also give a better radius on the short turn and open up the throats, I think there are very significant gains to be made with the factory heads.
I gotta set , my 1971 026 castings square port heads. 572 big block 850lift cam 15/1 compression make 810hp. I don't know what the Afr 377/385 heads 950-1000 hp. Send me afr 385 and I will see.😎
😂
Never ported a set of rec heads, only oval. But I will all but guarantee that you will never get a pair of 049's or 781's to work like the AFR's.
I could make you that power with the #781 #049 casting heads but i
I have a magazine quoted figure of 650hp with factory GM iron rec port open chamber heads 2.19" in 1.88" exh on a 509ci 4" stroke 4.5" bore chev with the comp cams magnum solid roller. If I remember rightly it had a out of the box Weiand intake, on #7535 and 1000cfm 4150 flange Holley carb. And made in the 800hp region with nitrous. 9second quarter mile combo.
Yes you can but should you? If not restricted by rules I'd say don't try to make irons outperform aftermarket aluminums. There's a 2013 Yellow Bullet thread with Chad Speier worked 088s that I guess made 841hp na in a high cr truck pull application. 2.3 valve, epoxy, 374/385 cfm ar 1". Can be done, not sure if he's will to do the iron stuff anymore but for the price/time I'd start with something else unless I was boxed in via rules. He's gotta video on them too about a year back.
Nothing wrong with a basic port job if that's what you got but to make them great takes a lot of effort.
Buying a bare set of promaxx as cast and porting yourself, parting yourself/machining at a machine shop that does race engines/heads... might be the more budget friendly way to go.
I think you can maybe matchbthe summit but remember both aftermarket heads are probably running raised exhaust ports with help the flow number quit a bit. Factory to AFR, i highly dought it could be done. Would have more money if the stock heads then just buying the AFRs. My 2 cents.
I was going to say which someone brought up that you already have dyno results for professionally ported 781 ovals. I’d say yes to porting the rectangular. 496 might like an even bigger port also.
I don't have ported 781s
Sorry. I thought you had run a bbc with ported 049 or 781’s. You could compare those numbers from a previous. Thanks for all you do
Rich we had ported sqare port heads off of a 427 vett engine I forget what year they were the car we had these on had a tunnel ram and a solid roller cam 700 lift we switched to a pair of brodax heads after milling and a good valve job we only picked up 1 tenth of a second these were on a standard bore 454 we were upset because we spent all of that money with so little gain and to show how good the factory heads ran this 1968 camaro ran 8.90s on motor in the quarter mile and 7.90s with a 225 shot of nitrous at a 170 mph this is going back 25 years ago, hope this gives someone an idea showing what factory heads can do compared to aftermarket with a time slip instead of a dyno number
Were you running a automatic transmission or standard transmission? I have a 68 Camaro with a 4 speed muncie m22 in it. It has a built 355 small block but I'm looking to go to a big block as I can't seem to get the torque need to have the power it had with the close ratio transmission it previously had. I literally could get rubber in all 4 gears. Now it is limited to 1st and 2nd, with a slight bump in 3rd gear.
@jsharp7260 you had different ratios in the previous transmission that's one thing. Instead of putting a heavy BBC in your car, take your small block and stroke it to 383 ci. with a Scat 9000 3.75" stroker kit. Be a lot less expensive plus with the right camshaft and tuning you'll be over 500 ft/lbs of torque.
@@hoost3056 Thanks for your advice on this. I do have some extra things that I wouldn't have to pay for such as machining and I have some big block things already. So it might not be to far off. I'm going to be looking into a forged crank for this build as well. So we'll have to see what becomes of this. Maybe in the future I will post my results on here.
Most never explore what the factory heads can do. You had great results with your 454 factory head camaro........there's guys out there that won't run those numbers with all the "best" parts in a 540 bbc.
I much prefer good factory headed combos
What do we have to do to get someone to compete with raylar on the 8.1l heads? Raylar customers all complain about their after sale treatment, and they screwd up the valve alinement on LT's "ugly truck 2.0". At what point did America allow for monopolized flip you over a barrel costs, with no support? 4000$ for aluminum heads is twice the price most other heads cost. Even summit fails the L18 headbolt pattern in support. The vortec8100 basically can't blow head gaskets, it cracks pistons first. The stock heads weigh more than I do lolol, and flow less then the 5.3l. Frankly I'd have thought someone would have matched the ls7 intakes to the 8.1l block with an aluminum head when the block was moved into the purely aftermarket in 2007/2009.
No experience with Rectangular port iron heads, but lots with large ovals. 781 heads can see big improvements from porting, on my engine to the tune of 632 lb/ft at 3200 solid cam single plane, 13:5/1 comp. 468 c.i. I doubt they'd touch anything made by AFR though.
,,, well, still wondering for about 53 years, port for port, valve for valve, chamber for chamber, all equal, ,,, is the iron worth how much with the less thermal conductivity ,,, ?
The factoty large oval ports ,make better power than the factory rectangles !!
All these Dyno graphs are awesome but we need to know more. Like what stall works best with what curve or even gear ratio to optimize engine output
In every scenario
No most stock heads will start cracking at the port volumes required to get that much horsepower
Ask me how I know, I have a set of junk max ported iron heads. The short side of the port is awful
Go with aftermarket heads and save your money
Richard. Love the videos. Do you have a video showing how a Gen VI 454 big block performs with an eBay turbo kit? Stock heads, stock cam is what I’m looking for.
boost just multiplies what is there-350 hp stock
@@richardholdener1727appreciate the quick reply sir
489 bbc 9.8 cr ported 990 rec port , preformer rpm air gap , 232 236 @.050 about .600 lift. made 624 hp 640 tq with a 850 elderbrock , 640hp 670tq with a 950 holley
Wondering if you have heard of performance world heads, wonder how they stack up against the afr heads
What’s the compression on the motor
Approximately 10:1
I myself have a vortec 454 gen 6 and would love to get the AFR heads, but I am curious to know what the 279 heads would do with porting. How would they compare to the summit heads? Is that something that could be done in the future? Looking for all the torque for towing!!
You'd certainly pick up some nice gains by porting the stock rectangle ports, but IMO you're not going to make up this much difference. Plus, by the time you spend all that money to get it done, you could have bought the AFR's.
The AFR looks like CR went up, did it? Or was all that torque from port energy alone???
Richard
This all depends on cost - AFR Aluminum heads cost $3500.00 partially CNC
Summit only shows aluminum heads @ $820.00 ea. complete no more cast iron heads available
So I'm in the head business I run BBC Iron Heads on my own engine = WHY because I already had the heads and I don't charge myself for the work --- LOL
OK - There is no one in the country CNC porting iron heads it is way to detrimental to the machines and water soluble oil is not the best product to use on cast iron so a coolant change @ 50 gallons??? Now you're at hand porting - not fun - and time consuming - I charge more if the customer want iron heads ported - getting the two ports to flow the same or close - good luck with that on GM heads but it is possible to get them close with a lot of flow bench time - yuck - the heads weight 65-lbs each bare, and lift them up on the flow bench - OK (superflow 600 serial #001) Now they're ported, we have to fix the valve guides, cuz who wants to run 3/8s valves - LOL --- Where do you want to go here 11/32 or 5/16s - liners are ok for the EXH - but to do a good job on the intake you have to knock the guides out - AND - you can't put the factory guides back in because they drill the guides after they put them in the heads, so replacement guides, I use PEP bronze guides for that, you can get them in either 11/32 or 5/16. That done lets cut the seats on the SERDI Machine and cut the guides for seals, springs and be sure the spring height works for the springs the cam requires - What CC's do you want in the chambers, cuz you can only cut the heads so far until you run into the intake valve seat, WHY well by the time you get the chamber to flow correctly it CC's out at about 135, you can angle mill um about .125 off angle but then you have to fix the intake manifold side and all the bolt holes (@ about 400 bucks extra) If'n you already own the square port heads this is going to cost you (less the freight) about $3400 bucks $3900.00 if you get um angle milled - then how much did the valve-train parts cost you and the valves? - Which are not included in that price
OK - Great - Here's the catch 22 on this --- if the iron heads flow close and the valve size is the same and the compression is the same the iron heads will make more power, then the aluminum heads, so the only savings you get is the weight differential, to get your power back you have to raise the compression 2 points ---- If you have to run PUMP-GAS you are stuck with about 9 to 10 to 1 and hope it doesn't detonate the rings out of the engine -- OH OK lets pull some timing out of the motor - LOL - You're better off with a bit less compression and give the engine what it needs for timing
THAT'S MY 2 CENTS WORTH
So I found this At Summit a World Products CNC Iron SQUARE PORT HEADS
www.summitracing.com/parts/wrl-030620cnc/make/chevrolet
Using bore, stroke, chamber size while guessing at the gasket thickness and gasket bore, it's between 10.5:1 and 11:1 compression ratio???
Richard, are there any aftermarket street aluminum heads that will work good with flat tops...454? Seems all aluminum heads can only get with overly huge ports. I would like a step above the peanut ports. Not sure why manufacturers have not caught on to this yet. A small chamber but much better flowing than 236 and matching high rise intake
lot of after market heads have oval ports-AFR 265s are excellent
I would love to see you do some street-centric BBC builds and comparisons!
please see the many street builds up
@@richardholdener1727 I just watched the hunt for grunt videos - thanks! I'm building a 5700lb 68 Impala and the videos really helped point me in the right direction.
Question for you unrelated to the heads: Was this comparison done on a stock GM block? 2 or 4 bolt? If 2-bolt, are you comfortable with stroking it and making these power levels reliably for a street car?
this was a gen 6 block that all have 4 bolt mains, but I would run this on a 2-bolt as well
I've always wanted to see a test where you trade off head for cam - i.e. it takes that 300 roller to get to 630 hp on that BBC with stock heads, how much smaller/more streetable a cam could you run with the AFR's and still hit that 630 hp performance level? I also wish these published tests would record idle speed and idle vacuum values so readers could decide if they could live with the street manners of a given cam, if they could run power brakes, and so-forth.
this is not a good street cam for idle quality
I'd say your way better to go aluminum. I personally much rather have 600hp with Afr heads and a super mild cam
I'm wondering what, if any difference a open spacer might have on that last test pull?
I thought the whole point to aluminum heads was to lose weight off the front end of the vehicle? Not a power concern, certainly...
Yeah even fully ported the stockers won’t match the AFR heads.
Could be right, hard to say (these 290s vs same flow bench/same dyno/same day). Can't really compare different flow benches with AFR advertised vs people that sell 088 truck pull stuff so 🤷♂️
Can make em pretty good though. Even though it's totally apples to oranges with different benches and maybe different methods (inlet radius...) Speier's 088s seem comparable to the AFR 290 and look like the outpace it on the upper end. Apples to oranges, dunno
How about some E85 test?
Just switching fuel can gain 100HP
plenty of e85 vids up-we never gained 100 hp just by changing to e-85. on a boosted ls with no timing or boost change, it was more like 35-40 hp
Hey Richard I apologize if you ran this test on a video already but I want to know is it worth putting a tunnel ram on a almost bone stock gen 6 454, what would be the HP/torque with stock heads and cam ECT ?
it would make more peak power than the factory EFI
Can u help me rebuild my 383 stroker I need help on what to buy and what would be needed or who to take it to all that
No , not with out spending more money, and exhaust we never flow like afr
Oobie doobie! 496!!
Do you sale engines? I'm interested in buying a big block chevy with plenty of torque to go in a square body crewcab dually.
Sorry-I do not
I have a 489 with a roller sets up and a 525 ish cam and 781 ported heads . How much more power would I gain with a set of aftermarket heads. compression is about 10 to 1. on pump gas and a 850 carb?
no way to know-don't know your cam specs (lift tells us nothing) or how well the 781 heads are ported
duration on intake 235 exhaust 242 at 50 lift is 521 intake 540 exhaust 110 center 110 lobe separation 225 intake and 188 exhaust
mild port
When doing these why isn't any info on valve size, port CC. All make huge differences. The aluminum heads allow for more time
more time for what?
@@richardholdener1727 more timing in the engine.
Not just porting but very little porting by a professional because there already too big
My comment was deleted? Port/polish ftw
What was the cam you used?
was it not given in the video
AFR FTW!!
Can we please stop using these strokers for these test. Most guys just have a .30 over 454 or maybe a 402. These just don't apply to the average guys power plant.
Did you listen to anything he said? It's not about the motor the heads are on, he's showing us differences between the head options. You can apply this information to any big block...
Yeah the strokers are only used to tax the heads more and show the differences better. You can figure it out mathematically by dividing the HP/TQ by 496 then multiply the result by 468 for the .030 over 454. That will give you a rough idea.
@@permafrost2064 incorrect. You are grossly over simplifying.
@@DBSSTEELER numerical theory is far different than real world. You can extrapolate though you will have far too many variables for accuracy in prediction.
@@scoutdogfsr care to elaborate? It sounds like you fancy yourself an expert.
Lol at Hefty Hefty Hefty.... wonder how many yutes will get that reference