8 3/4 Chrysler pro gears?

[SSDiv6]

Originally Posted by Dwight Southerland

It's called hypoid distance. Dana 60 is 1.125". MoPar 8 3/4, GM 12 bolt and 10 bolt, AMC Model 20 are 1.50". Ford 9" is 2.25". The farther the pinion is from the centerline of the ring gear, the greater the angle of the drive teeth to the ring gear teeth and more friction. Bearing size is a factor for efficiency as well as rotating mass.
I remember that same article, but have since learned from other sources who have done serious experimentation that the Dana 60 is more efficient than the 12 bolt.

Dwight is correct; after much analysis, the final result is the Dana 60 is the most efficient of the bunch.