Hemi and horsepower? An early Hemi can't be too big, put out too much HP . . . or be too fast . . . but it can cost too much money If it was mine, I wouldn't mill/surface the intake -- if there is an issue with the heads being milled, then fix the problems with the heads and don't ruin the manifold. You can have the intake surface on the heads milled the appropriate amount (the math isn't that hard), then ANY non-modified manifold will fit.
I think that's the best route as well - doesn't make sense to me to cut the intake when the heads/block are causing the problem. Fix the heads & don't worry about it again. This ***umes that you have checked the valve clearance and all is good there.
but is the difference due to block milling or head milling? If you mill the intake faces, but the deck of the head is stock, then you have ruined a set of heads? The Weiand dual quad is not that rare of an intake, I think you still can buy them new, and if you have to stack a couple of gaskets on each side to make it work on another motor, what's the big deal?
Have to 'pick your poison' someplace? I've had plenty of blocks decked and the LEAST amount possible is taken off . . . which has never caused me an issue with an intake manifold. My guess is that he either doesn't have a problem at all (except for thick intake gaskets) - or the heads have been milled more than once. It is much more common to see heads milled than blocks decked (in my opinion) - though I frequently do both! My only point is that he needs to figure out where the problem is coming from (and if he has one) - and if he can fix it so that ALL stock manifolds fit, that is how I'd go about it. The chances of him wanting to try a new/different manifold are probably greater than swapping to a new block or heads . . . once you start having to modify manifolds - you keep on having to do it. Also, why ruin a manifold for the next guy - these things are frequently p***ed around from one hotrodder to the next. Anyway, plenty of ways to fix it . . . everybody has their opinions on which way is best. The good news is that he has now read many replies that have the information he needs to make an informed decision . . . that is what the HAMB is all about --> you go to the fortune teller, then decide what needs to stick to your situation.
Your problem is not the 392 with 354 heads problem that those spacers are made for. Your problem is that the heads have been surfaced like DE SOTO said. Look for some different heads or have your manifold shaved.
I have a real 1957 392 375 hp engine here, the intake is off right now, just send me the manifold and ill let you know if it fits properly on mine, I just can't guarantee I'll send it back!
I had the same problem when I put a hotheads intake on my 354, the heads were surfaced too much. After oblonging some intake bolts holes it fit perfect and 4 years later has not been touched.
The part number on the manifold is listed in the PAW early Hemi catalog as fitting the 331,354 and 392 Hemis. Measure the width from intake port to intake port on the engine with heads attached and measure the width of the intake. I would use both the widest and narrowist points on both. It maybe an alignment problem with the port angles and these measurements may give you a good reference.
As has been already said, he would need those ONLY if he was running 331-354 heads on his 392. If he has 392 heads those will do him no good. I'm with the guys who think the heads have been shaved a time or two or the block has been surfaced or both.
I pulled a head and checked the thickness, it has not been cut. I decide to put it together with no intake gasket, and # 2 Permatex. Now I torqued the head bolts and one of them stripped the threads out of the block. I was on the final torque setting of 80 lbs. So Now I have to pull it all apart again, and helicoil. Always something.
Just how many Weiand 2x4 DeSoto manifolds have you actually seen?? As a side note, most Mopar types reserve the 'RB' designation for conversations centered on B vs RB wedges... .
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