As I recall exhaust manifold gaskets are not recommended with steel heads and stock manifolds. How about with aluminum heads and stock manifolds? Aluminum heads and headers?

Use silicon and no gasket.

Good question. John Mummert would be the one to answer.

FYI, I use iron heads with FPT copper header gaskets and FPT headers and have had good success. I also use studs (actually set screws with allen heads) and nuts. I think this evens out the torque load on all things involved. An added bonus is an easier installation and removal of the header.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

The problem is not so much the heads and/or the gaskets but in the use of cast iron exhaust manifolds. Using gaskets in conjunction with the cast iron manifolds does speed up the frequency of broken or cracked manifolds. A thin film of hi-temp RTV in lieu of using any form of exhaust gasket seems to prolong the life of the manifolds. Gaskets used with headers should not present any problems other than potentially being more difficult to cleanup the flanges when gasket replacement is required.

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On my Y powered roadster with aluminum heads and with steel header flanges, I do use high temperature RTVand no gasket. I do see evidence of some impressions being made in the cylinder head where the raised portion of the weld on the head side of the header is imprinting itself into the aluminum heads. That will be a problem down the road. On the dyno when using aluminum heads and headers, I do use copper exhaust gaskets but those do have a tendency to leak.

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With the exhaust manifolds being machined flat at the head mounting surface, then a thin film of RTV should suffice. For the same reasons the manifolds break when using gaskets with the iron heads, the manifolds will also break or crack when using them on aluminum heads with gaskets. Keep in mind that the exhaust manifolds for many of the as delivered Ford engines did not use any form of exhaust gasket at the heads and simply relied on a good metal to metal fitment.

Lorena, Texas (South of Waco)

Thanks for the input. Plan on running the cast iron manifolds on my Bird when I put it together initially until I can come up with enough cash for a proper set of headers. Only headers I have at the moment are a '50s set of Hedman's that are about done for. They are not much better than the factory manifolds. Will use silicone and go for it and save my money. Had sort of forgotten about the high temp silicone but I have actually used it before.

I don't have a recommedation re gaskets with aluminum heads.. however, it might be worth a note that in some environnments copper will react with aluminum.

Paul

Cracking, Heat Transfer issues? I notice the ones on my car do warp and leak after a season. Had one blow out at Columbus a couple years ago. Sounded like a very loose valve. Got home and found the manifold was no longer flat.

Frank/Rebop

Bristol, In ( by Elkhart)