I recently put headers on the 52, they are free floating from the intake manifold so they are not the root cause of an intake manifold leak that is effecting #s 1and2. I thought I had it fixed but now see that I am going to be pulling the intake. my ? is what sealer if any should I be using on the manifold gaskets. I have always used Permatex Copper spray in the past but the new can seems to be just colored spray with no body. I will be checking the manifold for warping.

The trick to receive a good non leaking mate for the manifolds is to bolt up the two manifolds with the 4 center bolts. When correctly mated the two manifolds should be trued up by either a machinist or with a special belt sander. If the engine had the alining rings insure they are fitted in the holes as required. This should give you a good leak free installation.