[Oldsmaniac]

Hmmm...Do you know that the factory did not use gaskets on the exhaust manifolds? It was a metal to metal fit on the head. To blow gaskets it is possible the bolts are not tight enough or are coming loose. You can also buy a solid copper gasket that should not fail as easy as the metal fibered ones. You could try and have your manifolds milled smooth and dont use any gaskets.