K code (Hi-Po) exhaust manifold gasket

Thanks for all the help guys. I still have a little bit of old gasket material stuck to the heads from the old headers I had. So I'm not sure if it would seal without a gasket. Actually, I cant' tell if it's old gasket material or a very thin layer of paint. How clean do they need to be?

Also, why do you guys suggest using a copper or aluminum gasket?

Okay here are the new gaskets I made today. I laser cut two out of some material that has a fiber core with perforated steel on each side. I cut the other two out of a material that has a perforated steel core with a layer of graphite on each side.

I'm not sure which ones to use. I think the graphite will seal better. We used to make the round "donut" gasket out of this material. The one that goes between the manifold collector and the exhaust pipe.

The perforated steel one is much more rigid. This type of material is commonly used on exhaust manifolds. I'm not sure how well it will seal because usually one side is either solid steel or it has a softer material on the other side. I have seen this type of material used on anything from Briggs and Stratton lawn mower engines to huge Waukesha engines that are used in the oil fields.

What do you guys think?

The top gasket is used. Bottom two are new.


A new gasket on top of the old one to show the difference in port size and location.


The old gasket on the hi-po exhaust manifold. Way off!


The new gasket on the hi-po exhaust manifold. That's more like it.