I got an original R block and I have always had to grind the rear main seal some as the ends always protrude over the surface. Could this be the result of a honing operation on the main journals or something like that? Its almost like one of the mating surfaces on the block or main cap has been ground?

The R block takes the same rear main seal as the 273-340 LA engines.

If the rear seal is flush with the pan rail on one side, it should protrude approx. .010-.020" on the other. Measurements should be taken off the main body of the seal and not the seal lip as they have a chamfer on one side of the sealing lip to fit the other half.

You should have identical measurements with the main cap and the block.


Greg

I will check it again and see just how far out the ends are poking. I think it is more than .020 but I will double check. It does seem like alot. Perhaps I can post a pic later today?

Pics are worth a thousand words