I checked the Fram that was on my '55, it has no drain plug. It fills from the side, and drains at the bottom. There is a tube inside that has a small hole about 2/3 the way up that the oil drains out through.
While we're on the subject of filtering, I'd like to suggest that you add a Filtermag. I added one to the '55, you'ld be suprized at what the filter misses in the line of metallic particles.
