[Stuckinda60s]

Now I'm wondering which way this problem should be addressed. Should the holes be elongated or should the head-mating surfaces have a cut taken on them? If the head surfaces need to have a cut taken, does anyone know how much it should be? How much has anyone taken off when they've addressed the problem? I'm thinking maybe .050 a side?

[6T5 Cat]

I've bought 4 Performer RPM manifolds for 4 different Pontiac engines I built over the last 10 years and I had to have each one of the manifolds cut .060 in order for them to fit properly.

[HWYSTR455]

We feel your pain, and are here for you! It's something you would THINK they would have corrected, but on other posts, it looks like they don't acknowledge there actually IS a problem. When I called the one time, few years back, I told them to just look on ebay at all the ones with cracked exhaust crossovers, that should be clue enough!

It's not limited to Pontiac intakes either, just did a swap from a Performer to an RPM on the Olds, BOTH had the same issue, had to have them cut. The RPM I didn't even try, I sent it right to the machine shop. Even they said "Wow." .

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[HWYSTR455]

Just did a google search with the string "Performer RPM cracked exhaust corssover" and got hits on Ford, Mopar, and Olds foums on it, so they have to know there's a problem...

FYI - I cut the Olds ones .050 and use thick gaskets ....

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