Both cars & trucks used that transmission. It is a SM318 with the short tail housing. As 3B stated 59-64 car also 63-67 truck. The truck didn't use the rear mount. Some had the casting but were not drilled out. Very common transmission.
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