[danielwetpaint]

Chevrolet is "owned" by General Motors. So is Buick, Oldsmobile and Pontiac (known as B,O,P). There is a difference in the BOP 10 and 12 bolts as opposed to the Chevy 10 and 12 bolts. The BOPs are smaller internally and therefore weaker than the Chevies. They look similar to each other,,if you are looking for a rear end to go in front of Horsepower avoid them. Most are identified by "C" shaped notches cut into the sides of the rear end cover.There are several
Chevy 10 bolts available,the ones we mainly use have a rear facing access cover and load the gears and diff' through that opening.The Chevy experts tell us that the rear ends are aslo identified by the bolts that hold the ring gear to the differential,not the number of bolts that hold on the cover.But we still bend over and count the cover bolts,,lol. The chevy 10 bolt rear ends are identified by the ring gear diameter.First was the 8.2(1962-1972) , then 8.5(1973-1988), then later 7.5 (late 70's up to current). The 8.5 is the strongest,it came in car and trucks.Some say they're as strong as the 12 bolts.I've never broken one yet. The 12 bolts came in two versions,,car rear ends (Chevelles Impala's,etc) and Truck rear ends. Several parts don't interchange between them,including the cover. My memory is bad, I'm sure I forgot a few points,or made minimal errors in the timelines,but someone else will chime in.