I just noticed your comment about oil on the rt motor mount. Check the side cover and valve cover closely for seepage. Oil running down the right rear of the engine could be making its way to this area from these.
Also, I know that the early full pressure 235s were not machined to take the neoprene seals. But, I don't know where the change was made. If the gaskets are ok, I think it would be wise to go back with a rope seal. Pull the trans far enough back to clear the pilot bearing, loosen the main caps and the crank will drop far enough to easily roll a new upper in place.
