I'm putting new gaskets on my intake and the gaskets do not have the holes for the heat exchange. It is blocked off on my intake on the top but the old gaskets had been modified with the holes added.... Do I need this flow?
Carburetor or fuel injection? Do you have a heat riser valve on one exhaust manifold? That crossover system is to warm up the intake charge for better vaporization, especially when the weather is cold. On some manifolds it warms up the automatic choke well also. Not so effective without a functioning heat riser to force flow. Other Georgians know better what you can get away with.
I've just had this dilemma on my 350 olds this weekend and spent hours reading all sorts of crap on the Internet; It will crack Ali manifolds ( I'd run with it on my edelbrock for 3 years + no issues) if you don't blank it off it voids warranty on edelbrock manifolds, blanking it off gives more power, but poor cold running, engine never heats up properly etc etc. In the end I've put 0.035" stainless shim between the gasket and the head and cut a hole in gasket behind the shin and clamped it all down, exhaust note is noticeably different, I'm due some dunno time so will report back
Carburetor and nothing on the exhaust manifolds. Electric choke. It's easy enough to add the holes like they had it before.
Hi KFC, Could you post a link to the "blank it off" instruction? About my first Google hit was this 9 year old general instruction from the Edelbrock web site just says be sure the heat riser is working properly ( opening after running a while) to prevent overheating the manifold. http://www.edelbrock.com/automotive/misc/tech-center/install/misc/general-intake-manifold.pdf I was thinking they would fill the crossover passage if it was such a bad thing.
Most of what I found was contradicting rubbish and I agree with you why have it if it's not suitable use. I had the same choice and decided that although I could cut the composite gasket I wouldn't want to expose it to exhaust. Mondello sell a blank for this purpose so I just copied the idea in a vague hope for a couple of hp
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