Is a 12 bolt out of a 70 Cutlass the same as a 12 bolt from a 70 chevelle?
Thanks

not if its the factory rear to the cutlass, if it is its really an 8.5 10 bolt with a 12 bolt cover. If its a mostly round cover with a smooth back (no oil channel in the upper part of the cover) then it should be the olds rear. Bolt in axles are also a giveaway to the olds rear. Try a search on the "type O" 12 bolt for more info.

Drptp is right,

But, the rearend should bolt right into any 1964-1972 A-body (Chevelle, etc) if you just need a rearend...

Supposedly, the "12-bolt" designation refers to the number of bolts holding the ring gear to the carrier, and NOT the number of cover bolts... Based on this, you would have to pull thecover to see if it was a 12-bolt...

I think (I have heard) the Chevy 12-bolt (car) did come factory in some 70's GTOs/Le Mans and maybe Cutlasses in the early 70's, but I am not sure if this is true, or which cars/years they were in...

And the basic strength of the Chevy 12-bolt comes from the size of the ring gear (8.875inch), not really the number of bolts. You often here Chevy 10-bolts described as 8.2 or 8.5, which also corresponds to ring gear size (as does the Ford 9-inch)...