HP MANIFOLDS

I have a 440 six pack Cuda. I use felpro exhaust gaskets on heads and flange. They never seam to last more then about two years without leaking.

maybe the manifolds need machining. just curious what gaskets are the most popular for hp manifolds. thanks Rob.

If the flange mating surface is flat, you should not need any gasket....I generally install HP factory manifolds immediately after painting an engine in an effort to promote some sealing, but never had to use gaskets, if your manifolds are flat try putting some paint on the manifold mating surfaces and torque in place, allow the paint to dry......

They were installed from the factory without gaskets. They easily warp. Remove them and lay a straight edge on the ports and you will see why the blow a gasket. They need to be milled flat.

you would likely have better luck with these Header gaskets.
https://www.summitracing.com/parts/fel-1414/make/chrysler

For best luck apply high temp silicone to each side let sit for 15 minutes. then install just snug. wait and hour or two and tighten. as with most things run then retighten while still warm.
maybe go over them a week later.

that said apply high temp silicone liberally to exhaust manifold same procedure is likely all you need.

Do you retighten them after driving it with the new gaskets?
If not do that several times when it is cold until they don't tighten anymore: scope:

Remflex gaskets are designed to crush some with tightening to make up for less than perfect sealing surfaces on the heads and manifolds.

Thanks to everyone for your response. I will remove manifolds and check straightness. Rob.

Clean every thing up. Ultra copper around the ports and assemble. Just snug the bolts lightly. Let it cure over night and torque to specs. You can recheck cold after a few heat cycles.

Thanks Nitrousn.

Like I said, you will have to take them off to clean them and put on a new gasket. Check them with a straight edge and you will see the warp in the middle. Mill them flat and your done.

I’ve also use the ultra copper with success.