Nathan - According to what I could find through my resources, 1959 was the first year where a 1/2 ton Positraction option was listed in dealer documents. This one originally dated September 1958 for 1959 Chevrolet Pickups on the last page (screenshot below) shows that listing. No idea if it would fit earlier 1955.2-58 rear axle housings???
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
