Exhaust Leak
 

I have a 1995 Damon Intruder with the Chevy P- 30 chassis 7.4 engine.
I rebuilt the engine this summer and the exaust gaskets were replaced. These gaskets were the same as the old ones and the old ones leaked. When I looked at the gaskets on the corner there was only about an 1/8" of gasket under the manifold. and they started leaking within 100 miles. I am thinking these are diff. exaust manifolds I need gaskets to fit these manifolds

Last summer I replaced a broken exhaust bolt on our 1995 chevy 454 in the P30. I vaguely remember reading that it was best to not put gaskets between the head and exhaust manifold. Actually use a high temp anti seize between the two, this was because of the manifold expanding and contracting. I tried to find the reference I'm referring to but I can't find it anywhere. I did find another repair manual that talked about cleaning the old gaskets off and putting new gaskets in for the intake manifold, but the exhaust manifold instructions did not have any reference to any gaskets.
Again this is a vague memory so you would have to do more research to validate what I am saying.
Good Luck!

I would clean surfaces then coat with light layer of high temp silicone torque down.Get engine warmed up then retorque. dave

Also check to make sure your manifolds are not warped and the ports match the ones in the heads.

The manifolds are most likely warped as mentioned by dakratdave mentioned. They originally came with no gaskets. If you want to use gaskets get some high performance ones from a speed shop or any place that sell high performance parts.

Chuck

X2 with chboone, get a set of header gaskets and coat with anti seize. They are a little softer and should seal for you.

I had the gaskets replaced a year or so ago on the 82 PA 454 and they started to leak, so I took it back and they used a gasket that is paper\cardboard type material with metal doughnut around the center. So far it is so quite unbelievable.
Tim

DGAR1956

As others have stated your manifold probably is warped, or maybe pitted. If you can't get it to seal with a gasket, a good machine shop should be able to resurface your manifold for about $100 or less. This should work assuming the head, at the exhaust port/s are clean, not pitted and true.

Hope this either helps or gives you another option. Merry Christmas.

Tom and Barb
2000 Bounder 39 Z

Permatex Greatstuff, Its a black high temp silicone, I use it on race headers all the time. If you have pitting it will fill it nicely, run a flat file across the manifold to check for warping.

exhaust leak
 

The exhaust manifolds on those are notorious for warping and leaking. My advice is to find a company that makes tubular replacement manifolds, the dissipate the heat which the originals don't .

If you go the header route, get them with as thick flanges you can, at least 3/8"

Chuck