I have not heard that the Chevy and GMC differentials for 1970 were different. I also didn't think that they came with positraction. The full floating front loaders from 67 to 72 have pumpkins that will bolt in to the 49 3/4 Ton. They made 4.10 gears for the 3/4 Tons with automatics.

By the way the standard ratio for a 49 3/4 Ton would be 4.57 and the 5.14 is for the 1 Ton.

1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed

My Chevy Master 4 Door is on the Road!