Performer manifold fit problem

[willysjeepseller]

In short the performer dual plane that I have does not fit well. The bolts were hard to get in the first time I installed it with the thick felpro gasket only, about 5 years ago. This time I followed the instructions and used the metal pan gasket and the felpro gaskets. I could not get the bolts in. I ended up enlarging the holes. I also had to use the rubber gaskets on the ends with silicone to make up the almost 3/8" gap. Well it only lasted a few runs and now the seal is gone. I was going to order a new manifold (same one) but i'm scared. I really don't want to go to a 4 bbl adaptor and use my 80lb stock manifold again???????

[willysjeepseller]

Only other hint I have is that the rebuilder said it was the big valve heads. Also the PCV guard pan from the stock manifold did not fit the performer. The edelbrock tech could offer no advice.

[jeepsr4ever]

When using the metal gasket with the thicker racing gaskets you have to cut the metal gasket with a tin snips everywhere BUT the exhaust crossover and then use Silicone RTV on the ends of the block and give it a LARGE 1/2" bead and let it setup until it is pretty rubbery and you should never have an issue.

[tufcj]

Have you had the block decked and/or heads milled?

It sounds like you have, and the gap between the heads is now narrower. Typically you need to machine the same amount from the manifold as the head is milled from each side, and 1.4X that amount from the front/rear seal area.

If you mill .015" from the head, then mill .015 from each side of the manifold and .021" from the front/rear seal area.

These are approx measurements. Measure and adjust for your application.

Bob
tufcj

[willysjeepseller]

Are you saying to use essentially just the pan part and not the raised seal portion? When the engine was rebuilt I am not sure how much they decked, they did not machine the manifold. I was wondering if this might be the problem.

[willysjeepseller]

Anyone have any numbers on how high the manifold SHOULD sit, so I can figure out where I am and where I need to be??

[willysjeepseller]

Finally got it all apart tonight. Can't see where the manifold was leaking but a rocker had fallen off the pushrod and intake valve. Things seem ok but how the heck does that happen? Nut was still down but rocker was sideways. End of the valve has some hammer like marks. I can compress it with a hammer handle and it seems to operate a little.?????????