Finally, you can install the rear main seal. This block was originally a one-piece rear main seal design, but it has been fitted with a two-piece seal adaptor. The two-piece design works with more performance cranks and oil pans than the one-piece blocks. In this build, we're using all Cometic gaskets. Use a thin bead of gasket sealer or silicone on the back of the seal (where it mates to the adaptor) and oil or extreme pressure lube on the lip of the seal before installing. Also, always make sure the lip of the seal points toward the interior of the engine. Finally, it's a good idea to "clock" the seal, or slide it so that the parting line of the seal does not match up with the parting line of the cap, as you can see here. This helps eliminate annoying oil leaks.