No, heads were not machined as the gaskets were evenly compressed. I cleaned
them with an emery cloth only and reinstalled them. Neither was the intake
manifold. Everything looked OK. The symptoms did not change after the
reinstallation. Compression was the same, no other surprises. Engine started
and ran OK. Again, I stress that the carb bottom rust looks awfully
suspicious. I do not suspect any head, block issue but I may be wrong. Rust
was present only in the area surrounding the intake: underneath the carb and
along the intake passages (see pictures).



Did you have the heads machined when replacing gaskets? Sometimes the
angle
between the head and the intake changes enough that the intake does not
seal
to the heads. Pull the intake and look at the gasket to see if it is
compressed all over. Auto parts stores do rent tools and you may be able
to
rent a pressure checker.