I can't answer your question with certainty, but if I found that nice of a box, I'm sure I could make it fit. There can't be a whole lot of difference on the rear part of the frame. Can you rob parts from the 60-62 frame (crossmembers/mounting brackets)?
Scott

Scott Ward

2 1948 1.5-ton Loadmasters
The red one and The snow pusher
1 1950 3100
1 1955.1 Chevy 6500
1 1954 Chevy 6500 2-Ton
1 1955 1st Series COE 5700
1 1963 K20 (454)
1 1964 C10 (350)
1 1951 1.5-ton Dump Truck
1953 and a 1956 Ford F800

Raising a teenager is like trying to nail Jello to a tree!