Question for the 351 Cleveland guys

[Benzo]

I have never seen a one-piece main seal for the Cleveland.

I have a stock 2 bolt main block with a 2 piece main seal. I dont leak and I run the engine hot and hard. I even have bounced the pan off the front diff. a few times.

The pan will need to be dropped to fix the leak, but it may not need to be removed completely. To change the rear main completely, you will need to remove the crank.

 

[OX1]

Unless there was something odd/wrong with your particular crank, it should be no harder to make that seal leak than any other engine that uses the 2 piece seal. It sounds like the mechanic was saying that seal surface was out of round?? (if thats what he meant by wobble).

BTW, I had a 95 F250 that a dealer did a rear main seal (1 piece seal) on (aftermarket warantee) and it leaked within a month. Sometimes there is scoring on the crank and it eats up the new seal quickly. They do make repair kits for cranks where the seal surface is torn up. It's a small thin sleeve that fits over that surface. It does require removing the tranny and dropping the crank to get it in though.