I used a '59 GMC 3.07 rear end under my '56. It was a direct bolt in deal with the exception of the bracket for the brake hose, which had to be moved to the opposite side. This is a Spicer rear end and if you go that route you need the complete assembly, including brake parts.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.