The short 3 speeed is 17" from the front of the case to the end of the tail shaft housing. The longer trans is 22". Internal parts will interchange as well a swapping the tail housing/mainshaft from one to the other.
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