Hey biggerbob . . . heads up on a rear-end out of '50 on ebay:
Complete Driveline

It's probably a 5 or 6 hour drive from Wooster. You might inquire with the seller if the '50 was a Power-Glide car and ask him to eye ball the numbers on the face of pinion gear. There will be a part number, tooth count, 'GM', a month and a year. If the gear count is 9-37 it is a 4.11. If the tooth count is 11-39 it is a 3.55.

regards,
stock49