I had the rear end cover off. I could not count all of the gears of course but I estimated 66 on the big spline and about 16-18 on the smaller. What kind of gears are these? Is a 12 bolt the right rear end on a 72 Chevelle. Thanks in advance!

Using my finger and a calculator you have between 4.11 and 3.73 depending on your estimates. Ring gear count/pinon
Many 72's had 12 bolts, this was the last year for them. Did you count the number of bolts on the ring gear?? that is the real count not the cover some cutlass's had 12 bolt housings with open 10 bolts inside.

Frank

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