I have ported cast iron exhaust manifolds, slant six and A.I.R 400, 440 manifolds but at that time they were six to ten years old. One trick I heard of but never tried was to stack exhaust manifold gaskets to make a straight shot before turning into the manifold. This could be very exhaust manifold specific too.
Good job! Thanks for the mention. I think the air pump holes on the end of the manifold go towards the back - never ran those things, just took them off and added headers 🙂
Yes, there is a normally a flanged metal tube that runs between the two manifolds, basically just above the top of the bellhousing area. You install it after you've put the manifolds on in a stock configuration. That crossover tube then taps off to a hose that runs forward along the side of the engine to the front of the block where the air injection pump is mounted to the front accessory drive belt system, typically below the alternator, sort of across from where the power steering pump is often mounted on the driver's side, although specific locations vary widely depending on body style, accessory configuration and era, obviously.
Charles a trick I did now my manifolds were 1986 fifth Avenue manifolds with four holes not 3 but I could raise the manifolds on the heads by grinding the holes open to bolt it to the head which allowed me to raise the exhaust ports a little which seemed to help allot in my case remember this was seat of the pants testing lop but it gave a straighter shot into the manifolds it's an idea I wanted to share .
Thanks. I ported the stock manifolds on my 1988 k3500 back in 88. That had air injection as well. They actually worked pretty well for a log style manifold.
Those holes and the tube aren't for *EGR,* they are for the *_Air Pump_* system. The EGR system, when equipped, is in the intake manifold, from the exhaust heat crossover into the intake stream.
@@servediocylinderheads Correct. The heads that have the provision for the AIR injection have little bumps in the castings, protruding up slightly into the exhaust ports, pointing back at the valve. Small passages are drilled from the flange area back up at an angle to those outlets that blow fresh air back up the port. The external flange side of the holes line up within those larger holes in the appropriate smog-type manifolds like you've got there. Interestingly, they were even used on some vehicles _without_ catalytic converters as at some times, in some regions, on some vehicles, they could still meet the applicable emissions requirements just by the additional air aiding combustion completion even without a catalyst downstream. For performance use when using a head with those little orifices, you just tap the holes (I think they're about a #10, so like a 10-32 or 10-24, IIRC) and stick in a little screw, bolt, chunk of threaded rod, or whatever and then just grind off the little protruding bumps in the ports to smooth them out... they're otherwise just like most of the other earlier non-AIR castings.
I also think the lump in the port due to the exhaust bolt location for the end exhaust manifold ports stick out in the way of flow from the cylinder head. I'd use a correct gasket to compare the difference in sizes from the cylinder head vs. exhaust ports to find out for sure. If the bolt lump is in the way like I'm thinking, I'd knock it down as much as possible and gradually round it off towards the port opening.
Flow the exhaust port with a typical header flange and pipe - similar shape to what a set of headers will be. Use that number as a baseline and comparison to factory manifolds.
As someone else mentioned the A body manifold on the drivers side has a MUCH smoother flow and it all goes in the same direction. If it would fit the engine compartment I'd run another one on the passenger side backwards. I hate the manifolds (like the ones being used) where the flow from the front and rear cylinders are pushing into each other as they encounter the cross flow of the center two cylinders. At least on the Chevy Ram Horns they turn so the flow is inclined in the same relative direction. It is impossible to clean up the bulk of the interior of the exhaust log. However, what I do is get one of the metal spiral wound really cheap drain cleaning tools at the dollar store. I cut it about 18" and solder it to a 1/2" copper pipe connector on the inside. This creates an eccentric motion when spun in a drill. I use really coarse paper (like 16 grit) taped on with a quality duct tape and then the paper is wound around the copper connector. I feed it into the manifold and spin it with a drill. It flails all over the place and helps to knock off rough edges and smooth the surface. I call it the "Wild Willy."
If I had still had some early B, C, or E body non EGR 340-360 manifolds I’d be sending them to you. Extrusion hone porting and maybe a little welding at the exhaust flange to match the 318 exhaust ports would be the bulk of the work needed.
I'd like to see this test done with the cylinder head exhaust ports modified to what they will be in the end flowing through the stock vs. ported exhaust manifold. I'm thinking the exhaust manifolds flow just fine for the stock ports of the head. But the manifolds become a restriction once the head can flow more.
I was trying to porting one of these today, and they sure are hard to grind, one thing you can do os enlarge the exit to almost 2" instead of stock 1.75, on the driver side they are always smaller around 1.6, on the individual flow they arent going to do something but on the overall It should help. On the corner ports i belive It should make the flow better ifnyou Port them especially on the outside
They are definitely going to need the magnum exhaust manifolds. The 340’s in the E bodies by far had the best factory exhaust manifolds and I cut a full second off of my et and gained 6 mph on my 70 Cuda back in the 80’s. Factory manifolds suck
If someone could mill the center of the exhaust dump out that might prove beneficial, but Mopar really missed on the entire exhaust port shape. One glance at a W2 head is an eye opener. Just getting as much area as you can without cracking/breaking through is probably best as there's no fixing that shape. I too have tried grinding work hardened CI and it's no fun at all. Since you're only looking for 1hp/ci I think you might already be there if using modern pistons, rings, and oil control.
What I wonder about, with log manifolds, is how well each port will flow once the exhaust pressure starts stacking up in the area where they all dump into? Unless the exit is large enough to keep backpressure from building?
I remember reading years ago a dyno test on a mild 360 engine. First they used 318 exhaust manifolds, then switched to 360's. 4 or 5 hp gain. then the vaunted 340 manifolds, no gain at all.
I wonder if plating the inside of your manifolds would help to smooth them out and prevent them from getting hotter, could use copper sulfate tape up the manifolds to hold liquid in, fill with copper sulfate solution and change the angle and it will plate the iron in copper, then use a copper wire for the metal to replace the copper copper deposited after dumping the first copper solution. Copper rejects heat from the iron, would help turbo application. Also do it in the exhaust turbine housing and it would do double duty as a space filler. Cost nearly nothing also but time.
It would be interesting to see the effect of a trailing edge clay mould right between those 2 center exhaust ports where they dump into the siamesed port exhaust manifold, surely a trailing mould there will help flow 'a little' and would help in a running engine to avoid disruption between those ports as rpm and gas speed rises, not practical/easy to do in a running engine but interesting to do with clay on the bench. Nice work 👍
Thks Charles , it's HARD grinding for sure bin there done that but really appreciate what your doing . be nice to know what the difference would be on a running engine!
When you are done with this project could you please estimate the cost of your labor, materials and shipping. I know you are doing this for the kids but I would like to know if it is worth doing this to a general purpose 318.
It is not worth modifying almost all these parts. This is an exercise to learn and raise a few $ for St.Judes. I am keeping track of all my hours on each piece. Cost would be crazy. I am not used to workin on Mopar stuff so add on some time to figure things out. Thanks
Before it is all said and done I will give my opinion on what should be done for a great running 318 with some elbow grease and good parts selection. Thanks
Never thought the headers on my 81 W250 318 were doing anything, stock engine. They were on it when I got it and finally rusted out. Had a set of stock 68 pickup manifolds so those went on it. Surprisingly it lost enough power to feel. If the truck was worth it I'd put new headers on it.
There are more efficient manifolds that came on the later 318 and 360 magnum engines. I don't know if you could use those under the rules you are working with. The early 340 manifolds are also a lot better, again not sure if you can use them. The worst part of those manifolds in the passenger side one, where the heat diverter valve is at, that exhaust hole is tiny on that side, I believe that it is only 1 5/8"...
@@servediocylinderheads I respect that there are, for a fact, very real, practical limitations to these things. I have only the mindset that those limitations may not be visible on exhaust ports without 1, using POSITIVE pressures to measure air flow, and 2, using VERY FINE grit surfacing tools to minimize drag and turbulence. I have even been pondering ways and means of copper cladding the inside of exhaust manifolds for [literal] molecular level smoothness. No promises, and I am a long way from that level of plating skills, or micro-polishing with what I have in my shop presently. The only part I have is some copper electroplating vats I got from a company that went out of business due to a fire which was [sadly] followed instantly by a heart attack [word is, the shock of the shop going up in flames, killed the owner literally while attempting to extinguish the fire]. So, out of personal respect, I dedicated the future of those vats to continue the service their former owner had devoted them to. At the moment, they are on hold, as a lower level importance at the moment, so they wait........
Love your videos and all of your hard work. My question is are you restricted 2 using 318 only parts the 340 manifold will give a significant gain in performance
Hi Charlie you know that you can normalize the cast iron by heating to a cherry red then burying them in a loam type soil you may need to do this twice
Those holes & the tube is for air injection from the air pump. Injected air into the exhaust stream for emission control. That particular manifold is a poor performer. The ram horn style off of a 360 pick up or van will flow better. The best would be the magnum exhaust manifold off of a 92 to 93 318 Dakota. 2 1/4 or 2 3/8" outlet & fits a 2 1/2" exhaust pipe. Depends on the restriction parameters. The 92 93 5.2 is technically a 318 & it is a Dodge.
I expected A body exh manifolds. No criticism intended. Love the info. But if Tony puts it into a car it's most likely an A body. That was the original concept.
A lot of work, wow
The step-by-step is fascinating, thanks!
Keep the reports coming and I'll be watching.
Thanks Again!
Glad you like it!
Ancient hotrodder saying:
Bad headers are better than good cast iron manifolds.
A most accurate truism.
I have ported cast iron exhaust manifolds, slant six and A.I.R 400, 440 manifolds but at that time they were six to ten years old.
One trick I heard of but never tried was to stack exhaust manifold gaskets to make a straight shot before turning into the manifold. This could be very exhaust manifold specific too.
Good job! Thanks for the mention. I think the air pump holes on the end of the manifold go towards the back - never ran those things, just took them off and added headers 🙂
Good move. Thanks!
Yes, there is a normally a flanged metal tube that runs between the two manifolds, basically just above the top of the bellhousing area. You install it after you've put the manifolds on in a stock configuration.
That crossover tube then taps off to a hose that runs forward along the side of the engine to the front of the block where the air injection pump is mounted to the front accessory drive belt system, typically below the alternator, sort of across from where the power steering pump is often mounted on the driver's side, although specific locations vary widely depending on body style, accessory configuration and era, obviously.
@@drussell_ Air injection pump? You mean lawnmower supercharger? 🤣
@@brokentoolgarage
They make a good crankcase evacuation system.
@@hotrodray6802 Oh yeah, I forgot about that. Poor man vacuum pump 🤣
It will be very interesting to see what kind of power this engine will make with these kind of factory parts. Endeavor to persevere!!
No quarter!!!
Yep, that's essentially the whole original point of the project. 😀
Charles a trick I did now my manifolds were 1986 fifth Avenue manifolds with four holes not 3 but I could raise the manifolds on the heads by grinding the holes open to bolt it to the head which allowed me to raise the exhaust ports a little which seemed to help allot in my case remember this was seat of the pants testing lop but it gave a straighter shot into the manifolds it's an idea I wanted to share .
Interesting. Thanks
All that work for no gain. Those manifolds are soul crushers! 😂
No kidding...boo hoo.
There is no crying in hot rodding.
Fairly uncharted territory. I know it has been studied by others, but I love the new attention.
Thanks. I ported the stock manifolds on my 1988 k3500 back in 88. That had air injection as well. They actually worked pretty well for a log style manifold.
Those holes and the tube aren't for *EGR,* they are for the *_Air Pump_* system.
The EGR system, when equipped, is in the intake manifold, from the exhaust heat crossover into the intake stream.
I should have known that. They pump air into the exhaust so the cat has fresh o2 to burn.
@@servediocylinderheads Correct. The heads that have the provision for the AIR injection have little bumps in the castings, protruding up slightly into the exhaust ports, pointing back at the valve. Small passages are drilled from the flange area back up at an angle to those outlets that blow fresh air back up the port. The external flange side of the holes line up within those larger holes in the appropriate smog-type manifolds like you've got there.
Interestingly, they were even used on some vehicles _without_ catalytic converters as at some times, in some regions, on some vehicles, they could still meet the applicable emissions requirements just by the additional air aiding combustion completion even without a catalyst downstream.
For performance use when using a head with those little orifices, you just tap the holes (I think they're about a #10, so like a 10-32 or 10-24, IIRC) and stick in a little screw, bolt, chunk of threaded rod, or whatever and then just grind off the little protruding bumps in the ports to smooth them out... they're otherwise just like most of the other earlier non-AIR castings.
I also think the lump in the port due to the exhaust bolt location for the end exhaust manifold ports stick out in the way of flow from the cylinder head.
I'd use a correct gasket to compare the difference in sizes from the cylinder head vs. exhaust ports to find out for sure.
If the bolt lump is in the way like I'm thinking, I'd knock it down as much as possible and gradually round it off towards the port opening.
Flow the exhaust port with a typical header flange and pipe - similar shape to what a set of headers will be. Use that number as a baseline and comparison to factory manifolds.
thats AIR ports , the air pump , or aspirator check valve fed air into the ports .....if its ok to use the 5.2 magnum , they are vastly, better
As someone else mentioned the A body manifold on the drivers side has a MUCH smoother flow and it all goes in the same direction. If it would fit the engine compartment I'd run another one on the passenger side backwards. I hate the manifolds (like the ones being used) where the flow from the front and rear cylinders are pushing into each other as they encounter the cross flow of the center two cylinders. At least on the Chevy Ram Horns they turn so the flow is inclined in the same relative direction.
It is impossible to clean up the bulk of the interior of the exhaust log. However, what I do is get one of the metal spiral wound really cheap drain cleaning tools at the dollar store. I cut it about 18" and solder it to a 1/2" copper pipe connector on the inside. This creates an eccentric motion when spun in a drill. I use really coarse paper (like 16 grit) taped on with a quality duct tape and then the paper is wound around the copper connector. I feed it into the manifold and spin it with a drill. It flails all over the place and helps to knock off rough edges and smooth the surface. I call it the "Wild Willy."
Great idea. Thanks
Thanks for doing that work !
You are welcome.
If I had still had some early B, C, or E body non EGR 340-360 manifolds I’d be sending them to you. Extrusion hone porting and maybe a little welding at the exhaust flange to match the 318 exhaust ports would be the bulk of the work needed.
Thanks
I'd like to see this test done with the cylinder head exhaust ports modified to what they will be in the end flowing through the stock vs. ported exhaust manifold.
I'm thinking the exhaust manifolds flow just fine for the stock ports of the head. But the manifolds become a restriction once the head can flow more.
I was trying to porting one of these today, and they sure are hard to grind, one thing you can do os enlarge the exit to almost 2" instead of stock 1.75, on the driver side they are always smaller around 1.6, on the individual flow they arent going to do something but on the overall It should help. On the corner ports i belive It should make the flow better ifnyou Port them especially on the outside
Thanks
I agree with enlarging the exit. GM did that for the TPI engines. Can't wait to see the flow numbers.
They are definitely going to need the magnum exhaust manifolds. The 340’s in the E bodies by far had the best factory exhaust manifolds and I cut a full second off of my et and gained 6 mph on my 70 Cuda back in the 80’s. Factory manifolds suck
If we play by the rules it has to get done with these. Thanks
Those fancy 340 manifolds were basically cast-iron versions of short-tube headers.
@@drussell_ I like that.
They're quite plentiful in the junkyards. Send in a set to be played with
Geeze just a set of shorty headers would go a long way 😂
If someone could mill the center of the exhaust dump out that might prove beneficial, but Mopar really missed on the entire exhaust port shape. One glance at a W2 head is an eye opener.
Just getting as much area as you can without cracking/breaking through is probably best as there's no fixing that shape.
I too have tried grinding work hardened CI and it's no fun at all.
Since you're only looking for 1hp/ci I think you might already be there if using modern pistons, rings, and oil control.
What I wonder about, with log manifolds, is how well each port will flow once the exhaust pressure starts stacking up in the area where they all dump into? Unless the exit is large enough to keep backpressure from building?
Can we say,"Pumping losses"?
I remember reading years ago a dyno test on a mild 360 engine. First they used 318 exhaust manifolds, then switched to 360's. 4 or 5 hp gain. then the vaunted 340 manifolds, no gain at all.
Good info, I don't think these are bad really.
And headers???
I wonder if plating the inside of your manifolds would help to smooth them out and prevent them from getting hotter, could use copper sulfate tape up the manifolds to hold liquid in, fill with copper sulfate solution and change the angle and it will plate the iron in copper, then use a copper wire for the metal to replace the copper copper deposited after dumping the first copper solution. Copper rejects heat from the iron, would help turbo application. Also do it in the exhaust turbine housing and it would do double duty as a space filler. Cost nearly nothing also but time.
D.V. used a special coating on the intake manifold I did for him and the 743hp 421 sbc. Good thinking.
It would be interesting to see the effect of a trailing edge clay mould right between those 2 center exhaust ports where they dump into the siamesed port exhaust manifold, surely a trailing mould there will help flow 'a little' and would help in a running engine to avoid disruption between those ports as rpm and gas speed rises, not practical/easy to do in a running engine but interesting to do with clay on the bench.
Nice work 👍
I bet you are right. Thanks
Thks Charles , it's HARD grinding for sure bin there done that but really appreciate what your doing . be nice to know what the difference would be on a running engine!
I have run ported exhaust manifolds a few different times. Not as good as long tubes but not much worse than shortie headers. Thanks
When you are done with this project could you please estimate the cost of your labor, materials and shipping. I know you are doing this for the kids but I would like to know if it is worth doing this to a general purpose 318.
It is not worth modifying almost all these parts. This is an exercise to learn and raise a few $ for St.Judes. I am keeping track of all my hours on each piece. Cost would be crazy. I am not used to workin on Mopar stuff so add on some time to figure things out. Thanks
Before it is all said and done I will give my opinion on what should be done for a great running 318 with some elbow grease and good parts selection. Thanks
@@servediocylinderheads Thanks.
Never thought the headers on my 81 W250 318 were doing anything, stock engine. They were on it when I got it and finally rusted out. Had a set of stock 68 pickup manifolds so those went on it. Surprisingly it lost enough power to feel. If the truck was worth it I'd put new headers on it.
I can see that. Thanks
ive heard of people porting exhaust manifolds with muriatic acid. it might be a faster option without messing up ur tooling.
I have to deal with acid and caustic at work....no thanks.
those are actual stock none HP 340/360 manifolds . the ports on a 273/318 are differnt shaped .
😳
I do not remember in the original video that headers could not be used?
Headers will be tested later.
There are more efficient manifolds that came on the later 318 and 360 magnum engines. I don't know if you could use those under the rules you are working with. The early 340 manifolds are also a lot better, again not sure if you can use them. The worst part of those manifolds in the passenger side one, where the heat diverter valve is at, that exhaust hole is tiny on that side, I believe that it is only 1 5/8"...
I didn't measure both. Thanks
Question? how or what would one use to fill in the exhaust port heat cross over in head, or the exhaust manifold passages to help improve air flow?
Molten aluminum.
7:50 Is that all the more you were going to open that exhaust up???
I did more work but it made very little difference. Thanks
@@servediocylinderheads I respect that there are, for a fact, very real, practical limitations to these things.
I have only the mindset that those limitations may not be visible on exhaust ports without 1, using POSITIVE pressures to measure air flow, and 2, using VERY FINE grit surfacing tools to minimize drag and turbulence.
I have even been pondering ways and means of copper cladding the inside of exhaust manifolds for [literal] molecular level smoothness.
No promises, and I am a long way from that level of plating skills, or micro-polishing with what I have in my shop presently.
The only part I have is some copper electroplating vats I got from a company that went out of business due to a fire which was [sadly] followed instantly by a heart attack [word is, the shock of the shop going up in flames, killed the owner literally while attempting to extinguish the fire].
So, out of personal respect, I dedicated the future of those vats to continue the service their former owner had devoted them to.
At the moment, they are on hold, as a lower level importance at the moment, so they wait........
Love your videos and all of your hard work. My question is are you restricted 2 using 318 only parts the 340 manifold will give a significant gain in performance
Get me one! I will talk D.V. into running it. Thanks
I hope somebody can get you a set of Magnum manifolds. The early 340 manifold are too exspensive.
At first glance I saw magnesium not magnum 😂
So is it just being seasoned that eats burrs? I wonder if grade of ductile iron was better than the 80s . Need diamonds lol
Diamond burrs, I like it!
They don't have to survive for 100,000 miles. Make them paper thin!
They don't grind they are so hard!
Hi Charlie you know that you can normalize the cast iron by heating to a cherry red then burying them in a loam type soil you may need to do this twice
I actually didn't know that. I also don't plan on doing that. I would think warpage would be a problem. Thanks
@@servediocylinderheads
A pass on a surface mill is always a good idea.
Those holes & the tube is for air injection from the air pump. Injected air into the exhaust stream for emission control. That particular manifold is a poor performer. The ram horn style off of a 360 pick up or van will flow better. The best would be the magnum exhaust manifold off of a 92 to 93 318 Dakota. 2 1/4 or 2 3/8" outlet & fits a 2 1/2" exhaust pipe. Depends on the restriction parameters. The 92 93 5.2 is technically a 318 & it is a Dodge.
No gasket matching?
I don't do gasket matching. I always like a bit of an offset. Thanks
A machine shop could bore out those manifold exits. Not sure if that’s in the budget.
So far my budget is $0.
Block off the openings , fill with ferric chloride and let it eat! You’ll have experiment with duration and freshness of chems!
I expected A body exh manifolds. No criticism intended. Love the info. But if Tony puts it into a car it's most likely an A body. That was the original concept.
I don't know the difference. Thanks
Do what's happening with this project
Top secret D.V. ported open chamber head here for research and casting thickness. Not allowed to post yet. Stay tuned.
By GM or Ford
And then modify it!
wrong exhaust manifold
Oh well.
Nothing like wasting your time 😂😂
I am very good at it. Thanks
If TUNGSTEN won't finish it, you can always go to SiC or diamond burrs... ~( 'w')/
Is there diamond burrs?
Try and score a pair of the Magnum 360 manifolds, the HP 340 manifolds are stupid price and they might not flow as good as the Magnums.
Send it some. They're free at every junkyard.
That 318 will make 355 hp and 320 tq
With which intake? Thanks