I don't know how wide the rear end can be for a 36 but I would say you could probably use a 55-57 car rear end but not a 55-59 truck. An S-10 is also a good possibility. Maybe others have an opinion on this. There are lots of transmissions available from 55 up including a couple of overdrives.
The full oil pressure 235 is a good choice and will run forever. I know there are ring and pinion gears available through assorted aftermarket suppliers for AD & TF trucks but have no knowledge on the earlier ones.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine