I put the heads on my 57 392, and torqued them down on standard Fel-Pro head gaskets. I set the Wiend 2-4 manifold on and the bolt holes don't line up. This is a real 57 300C block and correct # heads. It looks as if I either need to take about .125 off of the manifold surfaces, or use Real thick head gaskets. (which I have thought about anyway, to lower the compression). what am I missing here, any thoughts?
I don't Know, The engine sat for at least 30 years, I got it about 3 years ago but it was not together. How can you tell?
If they are the factory block and heads, 392 intakes interchange with the 331's and 354's. Something must be off.
Found this on the internet. ...Despite the height difference between the 331-354 and 392 blocks, intake manifolds are interchangeable between motors (except for port size) since the 392 intake ports are extended, so that the port-to-port width remains constant
Hey Tom... theres a guy in Hayward that has a bunch of Hemis for Sale..I'm actually thinking about buying one of his 392's for my 34 Coupe.
Intakes should interchange 331-354-392. I would FIRST suspect the aftermarket intake - quite possibly it has been modifed. Too bad you aren't closer I could loan you a stocker to check with. Can you post some pics of the intake in question? Maybe someone can see a clue as to the problem.
There was another thread, with someone looking for a spacer to solve this very problem but as I recall he had early heads on a 392 or vice/versa.
It's your rockers. Box them up and send them to me - I'll send you a set that will work. All of my intake pictures are on my desktop, which I won't be able to get to until monday. That looks like your standard 2x4 Weiand. Is it new? I'm pretty sure there's never been a manifold cast specifically for running 331/354 heads on 392, but stranger things have happened.
Its 30-40 years old, but I don't think it has ever been run. As to the rockers, I went thru the hassle of adjustable pushrods about 45 years ago, NO THANKS.
If you feel the manifold is not sitting down far enough & you need Thicker head gaskets. The problem Prolly lies in the Heads have been Surfaced a couple times & the head is sitting Lower than stock. I had this Very problem on a '60 389 Pontiac in my F-100. I took it to the machine shop & surfaced the face of the intake and cured the proble, Only draw back is now the Manifold is for THAT engine. Put the manifold on with NO gaskets & see if your hole line up, Then you will know for sure the heads have been Surfaced a Bunch.
If you use 331/354 heads on a 392 block you will need to use spacers. Intakes are the same on all 331, 354, and 392. That is they are right up to the point where someone modified it in the past.
It's hard to tell from your pics, but those intake gaskets look real THICK. The stockers are only .050-.060" thick BEFORE installed (not sure how much they squish after you torque them. If your heads have been cut a time or two and those gaskets are as thick as they look - then they are making the situation worse! But!! an 1/8 of an inch per side as you suggest is a MILE. At that rate you ought to be able to measure the thickness of your heads with a tape measure!!!!! but seriously - can you measure the head thickness??? If you can do it accurately - we can compare to some virgin heads and see if there's something to that line of thought.
De Soto & Kerry are correct. Ok, you have the correct head casting number...the manifold appears to need to be raised...you are thinking that you need to lower the compression with fat head gaskets... Did you measure the combustion chamber volume?? A stock head will be 105-112 cc, the variance is due to valve face and depth in the seat. If you have less than 105 then the surface has been cut. On most engines it would follow that a cut would also be made on the intake face to get the manifold to fit, but, the intake face on a Hemi head is not easily cut. Someone got lazy. Have you checked piston to valve clearance? How big is the cam? Even with stock pistons you could have problems if the heads are in fact 'short'. Of course it is better to figure this out now instead of after the damage is done... .
http://www.hothemiheads.com/intake_manifolds/intake_manifold_spacers.html I talked to a Hemi friend and he said you need these..
Intake spacers are only needed if 331/354 heads are used on a 392. Sounds like milled heads to me, unless the gasket is the problem.
Sounds like the heads were planed or the block was decked. Might have to take some off of the intake. FWIW, I have had challanges getting the intake on, on the hemi in my coupe for similar reasons, but once I get some crush on the gaskets it's all good.
sounds like someone mentioned earlier, the block has been decked and or the heads surfaced, so now you will need to cut the faces of the intake, either on the heads or more easily on the intake manifold to get it to sit properly. Since you said it lines up properly with no gaskets, and that the gaskets are .060, allowing for some crush on the gaskets, I would take .040 to .050 off of the intake manifold faces. The down side is that now this manifold only fits a motor with the same decking as yours, unless you double the gaskets up.
These guys will make head gaskets in any thickness you want and they do have early Hemi Gaskets. http://www.cometic.com/domesticauto.aspx Now the trick is figuring out how much thicker - the .060 doesn't translate to the head gasket directly. When I get big block mopar heads cut .060, I have the intake machined .072 per side to make it fit. The angle of the intake faces is not the same on the early Hemis though. My guess would be about .045 thicker on the head gasket.
I wouldn't give up compression just to keep from milling an intake, or is it forged from unobtainium?
That's what I was thinking - but I was just giving some options to him. Those gaskets aren't cheap either, but at least they make them to your bore size so the compression loss will be minimized.
With a 1800-2000 lb Roadster, I'm not to worried about losing a little cpmpression. besides, if I bring the combustion chamber back to stock with, say .040 extra gaskets, it will still have the 9 1/2-1 CR. and way more horsepower than I need. Thanks for all of the help..
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