GMC, Dodge, and International have all used the Dana/Spicer 70 in 1 ton applications. Some of the Dodges and Internationals even used them on the front for 4x4s. You may be thinking of the Dana 80, which is a 1 1/2 ton axle, though it does see some use in Chevy/GMC 3500HD models.
The 70 has the same 10 1/2" ring gear as the 14 bolt GM full float diff. The 60 is a 9 3/4".
