[Cliff R]

OPH, thanks for the history lesson. As many diff's as I've set up thru the years most have been plain old 8.5 "C" clip variety, a few 12 bolts, and a few later 7.5's. There were transitions years between 8.2's and 8.5's but I thought that the 8.5's were pretty much the "standard" by 1973.

You mentioned someplace about 1977 half ton trucks getting 8.5's by 1977. I've seen 12 bolts diffs as late as 1979. Did they overlap for a few years like the 8.2's and 8.5's in the early 1970's?......

['ol Pinion head]

Originally Posted by Cliff R

OPH, thanks for the history lesson. As many diff's as I've set up thru the years most have been plain old 8.5 "C" clip variety, a few 12 bolts, and a few later 7.5's. There were transitions years between 8.2's and 8.5's but I thought that the 8.5's were pretty much the "standard" by 1973.

You mentioned someplace about 1977 half ton trucks getting 8.5's by 1977. I've seen 12 bolts diffs as late as 1979. Did they overlap for a few years like the 8.2's and 8.5's in the early 1970's?......

Cliff, On the half tons, the base 1/2 tons began receiving the 8.5 10 bolts in '77, while the Big 10 Chevys & Heavy Half GMC's received the 12 bolt truck axle.

My Dad special ordered a '78 short wide Silverado Big10 w the Big 10 pkg. Basically a 5/8 ton. Believe 1980 was the last year for the Big10 pkg.