What to look for when inspecting the heads
The first thing to look for is pitting inside the lip that seals the cylinder and the head (GREEN). If there is pitting, you will not have a good seal when rebuilding. Coolant will work its way into the combustion chamber. The outer seal (The one that uses the big black rubber gasket) can be made smooth by filling in the pits with J-B Weld (YELLOW), but it is WORTHLESS to do this if the other seal is not PERFECT.