390 Rear Main Leak..help!
My father has a very nice 1973 F 350 Camper Special that we put a 390 in out of my old 67 T-bird. When we tore it down to rebuild it before putting it in we discovered it was not the run of the mill 390 but most likely something similar to the PI 390. (police interceptor) We bored it 30 over, flatop pistons, cam, turned the crank, and new carb. The problem we have is a rear main seal oil leak. We have tried the lip type seal and the wiper type seal and have no luck in stopping this thing from leaking. Everything is put together correctly, my father being a master mechanic for a ford dealer for 30 years. He is stumped as to why it leaks. My brother has spoken with someone at catapiller and they told him the block is worn oun out at the rear main. I have never heard of such a thing and my dad is not buying it either. What is happening at the rear main that would cause it to wear out? This engine has never been hurt or run hard or "come apart" for anything to be damaged. Also, it did not leak while it was in my T-Bird. Any ideas on how to resolve this would be greatly appreciated!!