On the inside of the cover where the seal goes, originally it had a felt "washer" and the seal that you know of. Quite often the pulley will get a small grove worn in it from the seal and can leak anyway. The reason I mention all of this is that there is plenty of room to put in 2 seals, 1 right behind the other. I don't know about you, but I hate oil leaks. I have done this with my engine rebuilds and never had a leak...knock on wood. I believe NAPA has the seals, if not, I know Phil Heisey has them.