Two Piece Seal,
Check that the pin has been removed from the seal groove in the cap & fill the hole with silicon or a bit of alloy rod, make sure that it does not interfere with the lower seal half in the groove.
Apply a bit of grease to the crank seal surface, make sure you have the seal facing the correct direction then slide the top half of the seal into place around the crankshaft taking care to prevent the OD of the seal from getting cut on the sharp edge of the block/cap face until the seal is in a position of about 1/2" up at one end & 1/2" down at the other, now sit the lower half seal in place in the block where the end is approx 1/2" up, this ensures the seal ends will be correctly matched, now apply a very small amount of 'Right Stuff' to the cap mating surface just around the seal groove area & carefully refit the cap ( with rear main brg shell fitted
) & retorque.