460 OMC to Merc exhaust adapters

[haolecrab]

I recently installed Merc stock exhaust (manifolds and risers) to my 460 King Cobra's using Stainless Marine aluminum adapters. I keep blowing the gaskets, both on the head side (Ford) and the manifold side (Merc/BBC) All surfaces are true, and plates are torqued to 40 lbs and manifolds to 30 lbs. Any experience or suggestions for gaskets? I've tried Mr Gasket, stock Merc, and still get leaks/blow out. My next attemnpt might be FelPro's. Thanks:frown:

[MOP]

I have had good luck with the black automotive type gaskets, the ones with the thin metal layer between the sealing material. I have had some problems with the light colored thicker composite gaskets, both types require re-tightening after running. The composite ones seem to need more attention and should be checked a few times. The tightening sequence is important, always start from the middle bolts working out. I go snug then divide the recommended torque into 3 or more steps depending if the bolts go through the main manifold sections or through cast ears. Iron loves to crack so more steps are always better.

Phil