I am in the middle of a Transmission swap on "Thor", 1958 4400 / 235. It was definitely in need of a rear main seal. If your Oil Pressure is as you say 12-15 at idle, that's great.
If your Bellhousing doesn't look like this on the inside, and is relatively clean, then I agree with Dragsix. Replace the clutch and just drive it.
BTW: My clutch turned out to be an 11 inch.
~ Craig 1958 Viking 4400 "The Book of Thor" Read the story in the DITY 1960 Chevrolet C10 "A Family Heirloom" Follow the story in the DITY Gallery '59 Apache 31, 327 V8 (0.030 over), Muncie M20 4 Speed, GM 10 Bolt Rear... long term project (30 years and counting)
If you don't like driving yourTruck, you won't drive yourTruck..| Living life in the SLOW lane
