426 exhaust gasket leaks

[Semaphore]

Hello
My 426 Hemi keeps blowing out exhaust manifold gaskets
It has aluminum heads and cast iron heads
I have replaced them twice now
Is there stronger gaskets on the market

Thank you
Pete

[fy469rtse]

Did you mean cast iron factory headers ? ,
I would look at the straightness of the face to exhaust manifolds, lay face down on a flat table, if not straight,
I would linish these straight , if they were warped , bolts aren't going to pull these straight,
I would try and get these so flat on mating surface , that it would look like you didn't need a gasket
I wouldn't use the factory double tin ones, try a good leather or similar header gasket, look at hookers range
I always like to use a good high temp smear of silicon as well
Good luck with it,
Also consider are the bolts loosening up and allowing the gasket to blow out , lock those in

[Semaphore]

Yes sorry i meant cast iron headers
I bought them new from mancini racing.