Grigg,
I don't think it was a rear axle conversion. The rear is an Eaton. The front axle looks like a Rockwell design or style with square axle tubes.

Jeff


1937 Chevy (converted to 4x4)
1942 Chevy G506 1.5 ton 4x4
1958 Mack B model (on Chevy 1 ton 4x4 frame)
1969 Dodge Charger
1987 K30 Crewcab