Probably the best deal you can get is the FelPro oil pan gasket set. Runs around $20 at NAPA. It has all the gaskets you will need and the rear seal in neoprene. I suppose you could use a rope seal if you want, but why? The slant uses the same rear main seal as the B and RB big block. As an added bonus, you don't need to pull any main bearing caps to change the seal. It has its own retainer at the rear of the block. The hard part is getting the oil pan off.