Except for the larger center hole for the later 4 speeds the center hole and bolt pattern is the same car or truck.
4-11/16 fits cars from 55 to ?? trucks from 48 that have a 3 speed or SM420. 68 and later with a SM465 have a 5-1/8 bore bearing retainer hole. That is by checking Novak adapters info on SM 420 and SM465. Who knows how many thousands of guys have pulled a SM420 out of a 48/59 Chevy pickup and stuck a 3 speed or Muncie or Saginaw car 4 speed right back in as long as the clutch spline matched. The V8 truck bellhousing that came with my 48 in 1973 had the stock 48 torque tube trans, a 55 or later something car or truck 3 speed and then an M21 Muncie.
From there we need clear good quality photos to look at to get our brains to do the "oh, yea, I remember" thing.
This is a mid 60's V8 truck bellhousing 3815891
The big difference between car and truck and years of is how the motor mounts attach to the bellhousing.
60/62 trucks Had a hydraulic clutch that had the slave mounted on the passenger side. I don't know the casting number but those V8 bellhousings have some favor with traditional hot rodders who want to run a hydraulic clutch with a Chevy V8 and stick.
Get us those photos and lets see what ya got going with that unit.