CHEAP 400hp Pontiac 400 Build Recipe
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- Опубликовано: 29 авг 2024
- When building a Pontiac 400 or really; any Pontiac engine on the cheap you need to look at few things; namely the camshaft and exhaust. If you're running anything lower than 8.5:1 you'll want to increase compression to 9-9.5:1 by changing pistons or changing the heads.
The gains are assuming you're using a standard Pontiac 400 out of a big car like a Bonneville or Grand Prix. If you're already starting with a Ram Air III setup you're ahead of the game.
The recipe is as follows:
- Stock Pontiac 400
- Stock Pontiac #16 Heads
- Melling "041" camshaft 231/240 .470/.470 112/115LSA
- Stock Intake
- Stock Carb
- 1 3/4" Headers w/ straight pipes
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Hey dude, Quick question.
I just recently got my Crankshaft for my 400 engine back from the machine shop. The holes on the wheel (such as the ones at 0:04) Are over grinded im guessing, and broke through the sides of the counter weights on a couple spots. Is that going to be a problem? Any answer would be much appreciated!
@@ShuffleInMotion I've seen stock cranks with the same "issue". They've worked great in the past with the hitch of the added drag and aeration in the oil. The 326, 350, and two of the 400s we've torn down have been popped through the side - maybe there's something to it?
@@DailyCliche I see, That lessens the tension for me for sure. Perhaps there is! Thanks for the info aswell
I put a ‘69 428 into a 1974 Bonneville with a 323 axle ratio. I added Ram Air IV rocker arms that boosted my lift from .410 to around.450. I felt bad because it appeared to be burning oil every time I accelerated. One day I took off without my music playing and I realized that I was smoking the tires just under normal acceleration! I previously had this engine in a ‘65 Catalina with a 241 rear axle. Those tall gears didn’t spin the tires as easily. Of course when I had that engine in the Catalina it was equipped with two-four barrels. Two-four barrels is a “magical” setup on a big Pontiac engine. In spite of the tall gears I could smoke the tires forever!🤗 The point is: If you find a big Pontiac engine BUY IT! They are becoming rare. A big Pontiac engine allows you to built lots of power without spending too much money. I drove my Catalina for TEN years! It didn’t get the best mileage, but nothing ever broke. I spent money on gas, tires, and oil. (Smoked a lot of tires) Nothing ever broke. I can’t say that for the computerized junkers that I drive now. I still have that engine. I need to find an old Pontiac to put it in. Anyway, I love Pontiac engines and you will too if you can find one!
#13 heads on a 455. Solid lifter roller cam. 👌
new video on pontiac 400, there are people out there i have 78 400 with 6x heads that overheated last summer
LSX, the headers aren't a bad idea. You could gain some torque and power by cutting off the collector and going to a 2.5" merge mild steel collector or using Headers by Ed catalog advice.
My favorite is 068 cam for street use.
I agree Tommy Johnson. I put the "magical cam" in my 30 over 400 with 061 heads and 2400 stall converter. It launched my 4200 lb 73 Grand Am so hard that I popped my passenger side window roller out of the track and almost broke the window. And I swear it's got the widest power band for a street / hydraulic cam.
Basiclly a stock 400 h.o 360/445 with bolt ons. Throw some 1.65 roller rockers get a bit clolser to .518 lift another cheap bolt on.
Yep! There's a LOT left in these things. I'm trying to scrounge up numbers for the new Speedmaster heads. They're like half the price of the Edelbrocks and seem to flow the same or better.
Spend a weekend porting the heads and you've got a TON of extra free power.
@@LSxHunter im staying away from speedmaster. At least until i see better. Havnt seen the pontiac heads but the intakes i have seen a ton of issues and flaws from buddys. Pin holes, cracks, globbed weld repairs on new stuff
That’s the worry - I’ve never had an issue with the SBC stuff there’s not enough info yet so somebody has to take the plunge 😂
@@LSxHunter i guess so wont know till you try. I have seen it on sbc, olds, and ford so far. My understanding is they are Australian, with a foot in the U.S and the oarts are made in China. I guess thats why i get pro comp professional product vibes from them. I am more worred about core shift, bad cast, weak cast, lack of quality control
I'm trying this build on my 1976 firebird formula imma keep you updated any advice or updates to the build would be appreciated 👏
Thanks for sharing.
Rebuilding the 400 in my 78 Trans Am. Any recommendations on getting power?
Not bad for unported heads
Right?! They flow okay and it’s SUPER simple to fix the flow issues to make big power.
I have a 400 in my 1973 LeMans Sport Coupe. I'm gonna need someone to up my engine for me. This is too complex.
I need all this done to the 400 that’s in my 69 Firebird lol
Is there an actual dyno session for this engine? I see the infamous 8 valve relief pistons.
The 15cc dish would be matched with the 16 heads(72cc). 5cc I’d match with milled 6X-4s.
There is not an actual run for this specific setup but can be fairly easily replicated and has been by a handful of dyno guys. The numbers used are from verified runs and checked against real world examples as well as passed around to a few builders.
The absolute biggest gain is the exhaust. Factory manifold are “meh” at best, Ram Air manifolds are put on a pedestal but they’re way easier to deal with. It’s hard to compete with larger headers and a good exhaust setup.
@@LSxHunter what year motor did you use in this video
What can you recommend for a pontiac 400 with 670 heads
What’s the car and intended goal? The main concern I’d have is you’d be around 10:1 with flat top pistons.
@@LSxHunter I got the same question I got a 73 firebird with a 400 and 4x heads I recently just purchased a set of 670 heads and got them hot tanked. I want to know what's the best cam. I don't care about having to run 100 octane. Cars a 4speed. I just want to go fast lol
@@LSxHunter I got the same goal and a pontiac 400 ass well as the guy who just commented
The 670 heads tend to saturate at valve lifts around .420" - .425". So no need for high valve lifts. The Lunati 10511004LUN with .424" lift is the 400 cam with high compression. It is not in current production but Jegs says they will order one for you. The Lunati or Comp Cams valve springs are good.
What’s the compression ratio?
I have a 79 trans am 400 w72 4 speed car with 373 rear gears. I want a performance rebuild useing the stock intake carburetor and heads. What cam and piston size do you recommend?
Ls swap
youre not gonna get much more with a stock intake.
You seem to have done alot of homework on Pontiacs. What would your opinion be of using a 068 or 2801 cam in a 67 Firebird with a stock 10.5:1 326 HO 4-speed? Mine seems to pull hard to 3800-4k but flattens out past that. I believe they used a 066 cam in these and there is more to be had without getting radical.
The 068 would likely be a little bit milder but if you've got it apart the 2801 would probably be a strong candidate for me if I were to do a 326. The 068 is a 212/225 .410/.410 116LSA the 2801 is a 214/224 .440/.470 112LSA. They're really close in spec and the 2801 should still have great street manners in that package. I'd also recommend changing the valve springs or at least have them checked for pressure.
@@LSxHunter thanks for the input. Also forgot to mention that it has the Ram Air Restorations long branch manifolds with 2 1/2 exh with x pipe so breathing isn't a problem. I'd like to know why Pontiac built these so mild at 285hp then went to 320 hp on the 350ho in 68.
I have a stock 1968 400. 030 over #16 heads 3.36:1 rear end, Automatic I might take to the track I dont know yet,, but like to bomb around town at the moment there is going to be a 268H cam going in it, would this be OK or is there something better, I have a 280H in my chevy 462 thats in my firebird at the moment and I was thinking the same for the 400 but someone mentioned that that may be to much for the 400 good for a 455 but not for a 400 any advise would be great
You can turn a 400 at 5800 with the oiling troubles they have????
will these mods work on the 75 formula 400
should do a best set up for a 455 :P
Go for an maximum torque setup? I get could behind that.
@@LSxHunter I'm down :p I have the 455 with 96 heads. But dont know what's in it.
I'm running a 400 with eldebrock Performer Intake, 6x heads, headers,full magnaflow exhaust and a Holley EFI. How much ballpark hp do you think I have? Not original block so can't really give you that info since even I don't know
Having trouble figuring this out without the program or a dyno session
If you have the 6x heads mildly ported and unshroud the combustion chambers to achieve 205 cfm at .300 and 240 cfm at .500, along with at least 9.5 - 1 compression you could see 425hp with a Ram Air IV cam as used in this video. I helped build this combo for a neighbor 11-12 years ago and his 406 ci dynod at 430hp and 470 tq. A properly rebuilt quadrajet might make more horsepower and torque than your FI unit. Without porting the heads you will top out at at 400 hp. Call SD performance, Kauffmann Bros or Butler to have the heads ported, but make sure you have them unshroud the combustion chambers to maximize airflow at lower lifts. Look in Jim Hands Pontiac book for info on head porting and combustion chamber unshrouding.
how bad is it if we have the 7J2 heads on our 72 400? we are getting a comp XE268 cam and we have a edelbrock intake and 800 4 barrel carb, just picked up hooker headers but our weak link are those 7
J2 heads.. they do not even have the area to drill and tap end holes so we ordered the L brackets that at least give you studs to mount them to. Looking around for heads but thinking eventually we will end up buying the RPM performer aluminum heads but for now we just do not have the extra cash.
I'll let you know here soon 😂. I was going to put the 350 into the Firebird yesterday and noticed they didn't have the holes drilled or tapped. At this point if I was going to spend more than $1,000 I'd go with these ebay.us/EJRdaO. Likely the route I'll go.
A guy suggested the same cam you mentioned the 268, That’s what I am going with myself with the double rolller timing chain with a HEI distributor !!!
@@mellow7me we just got #46 heads off a 428 that have 72cc combination chambers. it's going to push up our ratio.. I hope not by to much. We would like to be able to run premium pump fuel with no pre ignition.
Get some 6x heads if you can find some, Or the aluminum heads
I have the same engine 72 engine, 41988, j72 etc with a 1406 in a 67 lemans . Not Sure what I am going to do to it yet. Itbe nice to get a replacement while it gets worked IMHPO. I have stock exhaust too, headers would also be nice but I wont be racing. I may be doing highway driving in it. very curious to know what gears I have too.
Bigger cam and more compression
As all smog era engines should receive 🙏
This build work on a 1967 firebird 400 motor?
Would you do same with 72 grand prix?
Is it possible in a Pontiac Formula 400 1974 with 4x head? I have a edelbrock aluminium performance intake,, large exausting and EFI.
Did the 4X come with the 400? Depending on if it was a 2-barrel or 4-barrel matters as well. The 2 barrels had 1.97" valves while the 4-barrel had 2.11".
@@LSxHunter it is a 400-4 (4 barrel)
For a pontiac 350, what combinations would be good with the ram air 4 camshaft
Way to big of a cam for a 350,it's actually to big for a 400 with streetable compression ratios,a 702 lunati or 2801 summit would be as big as I would go with a 9.5cr 350
The ram air 4 is only 231/240. It’s not out of the realm of possibility. If I wanted something street/strip I wouldn’t be opposed to it but the street manners might be on the edge. Personally I’d be looking at a 220-230 cam but you’d be leaving some on the table above 5000 rpm.
I am a bit late to this post. I have a tired, never rebuilt 400 ram air 3. She is not #'s matching but is period correct for my Goat. I'm aiming at 450 hp in either a full rebuild or a ls build. I'm looking for a strong street car that I could take on multi state trips with the family. $ for $ what is the better way to go? I have very little experience in wrenching however I did want to get my 8yr old son involved with this as I want him to have the same love in Muscle Cars. Thoughts?
updates?
LS in a Goat? (Gag me). Buy a Camaro, (they're a dime a dozen), if you want a cheap build, and sell the goat, and RAIII to someone who can appreciate it. Curious if your 400 has 48 heads on it? Still got it?
Did you do some bowl work on the heads to get the 9.18 compression and 100 cc volume on the 16 heads? I thought factory was 72 cc and 10.5 compression for 16’s.
The #16s w/ -15cc pistons and the milled 6x-4(85cc) with -5cc pistons both get you around the same 9.2-9.5:1. Likely got the two backwards in the explanation. Attempting to make these short and sweet 😉. Even with the work the 6Xs should still be $600 cheaper than the $16s if you went to buy them already reconditioned.
I have set of 16 heads. they have been confirmed 75cc combustion chamber.
@@maynardreed8374 I think the average I see is 72cc - did you get yours flowed as well? I'm taking averages from 4 different sets for these numbers. They're usually within 2-3% flow wise.
@@LSxHunter I have not. I bought them last winter. I was getting ready to bring them to the machine shop and then covid hit. they are wrapped in plastic waiting until I dare to spend the extra money to get them done. we did check the combustion chamber size however.
I'm NOT understand why you went with the old OEM 041 cam when you could have got a modern cam ground by a computer, which would have had a lower spread between the advertised duration and OEM duration (for more power across the band), and a higher valve lift than the OEM cam.
For comparison sake for OEM vs what’s available. Personally I’d use a higher energy 041 like you’re talking but there’s a HUGE set of guys running stock small cams for some odd reason
@@LSxHunter I have seen test comparing yesterday's cam with today's modern cams. AT THE SAME dur at .050s, it is as much of a difference of 40 hps. When building an engine, you want to spend your money on the cam and heads to make power.
I checked out your channel, and see videos promoting LS's. Seems a bit contradictory. I like your opener on your channel, stating no Ls's, and then proceed to see videos pushing them. This particular video is relevant to your intent to keep our indians alive, and can appreciate it. Just wish your channel was a bit more dedicated. But thanks for trying.
Butler pontiac does LS too soo theres that
@@Braapcity guess you gutta go where the money is.
I just like building stuff man 😂. I also drive a Hemi and have worked on 4.6 ford stuff
far better choices in cams available.
Does anyone know if 46 heads will work out okay for our 400 build? they came off a 428 and we have a 1972 400 with 7J2 heads that have 96cc chambers and I am wondering if the 72cc 46's will push our compression up by too much such that we could not run premium pump fuel and avoid pre ignition.
I hope some answers your question, I have the similar situation. Just don’t know how many cc the stock pistons are. If you could determine that use one of the online calculators from Summit racing etc to determine Compression ratio.
I came up with 10:36 using Wallace racing compression ratio calculator. You can’t get it down some by using a thicker head gasket. Just look up all the head gaskets from summit racing and they will list many different sixes. Get it where you want it.
You will have to google Wallace Racing compression calculator. It’s easy to use. I tried posting the link but it gets deleted. Hope this helps.
@@figurefour633 Thank you for this advice you helped out allot! Not sure if we can get it down to 9.6:1 with just a thick head gasket. Maybe.. I doubt it. Maybe with a combination of milling the combustion chamber a little and a thicker head gasket.
@@81brassglass79 you can run it on pump gas 10.1. 93 octane
Why r you going with these cams...and such large dishes?
Cheap, easy, effective. I’ve got other engines in the 10-12:1 range.
@@LSxHunter cam grinds all cost the same..why NOT go with a better designed camshaft than a 55 year old version to increase power output..?
No way it makes 400hp