Technical Copper or Composite Exhaust Gasket?

I am mating iron exhaust manifolds to iron heads on a Ford 460 and can't decide whether to use an SCE embossed copper gasket or a Fel-Pro laminate composite gasket. I did have to mill the manifolds flat again since they were warped about .020" taller in the middle than at the ends. I'd like to do this once and only once.

Thoughts?

 

Ford never put gaskets on them from the factory. The gaskets will burn out and leak. Being a 460, they are real bad about warping. I have seen many of them with the bolts broken off flush with the head. Not sure if the bolts broke, allowing the manifold to warp or if the manifold warped and broke the bolt !!!

 

This is an old controversy, “to gasket or not to gasket, that is the question”. I would make sure both surfaces are flat, coat the manifold with “ high heat sealer” bolt on quickly, while sealer is still tacky. Just my 02.
If you are not comfortable with that, use the thinnest gasket.

Bones

 

Been thinking about "O" ringing mine with brass or copper rings. Maybe brazing rod.

Ben

 

no gaskets...can't remember the product name but black hi-temp exhaust goop is best IMHO

 

I had a set of headers on a sbf that I had problems keeping gaskets on. Tried the copper ones, they were too hard to seal. Found some dead soft layered aluminum Mr Gasket brand at a swap meet, peeled them to half thickness, used half on each side, never leaked again. I have used the copper ones on sbc’s before and they sealed fine, might have just been the last set I bought were too hard.

 

Tried the composite on mine twice before I bought the copper. No trouble since the copper.

 

Remflex
http://catalog.remflex.com/mobile/Category.aspx?id=150

 

I think I'll go with the copper. Heard it promotes better heat transfer between the manifolds and heads which helps preventing warping.

 

Copper over the composite for sure. I'd even try a hi-temp copper spray and no gaskets. Any SBC exhaust manifold I've ever put on an engine... no gasket.

 

op says he's using cast iron manifolds on cast iron heads. no gasket required.

 

As said before, Ford didn't use gaskets. The head surface and manifold mating surface were Blanchard ground at the factory. I worked for Ford dealers many years and every Blanchard Ground Ford that someone installed gaskets on, leaked. Sometimes warping the manifolds so badly that new manifolds were needed. Only the above ones ever leaked without gaskets. In normal service, flat, straight manifolds and heads should last a lifetime.