Can someone plz tell me what rear end comes in a "81 Elcamino?? Ive seen on here people swapping in a 8.5 out of GN or a 442. Is it a 7.5 ?? Plz somebody help im about to order parts ,, How can you tell the difference if they are both 10 bolts?? Thanks!!

Yes all 5th gen (78-87) all come with the 7.5 and they are not vary strong rearends. The reason people put a 8.5 rearend into there El Camino is becuase they are easy swap that bolt right up and only need .5-1 inch or driveshaft cut. Other then that there is nothing else needed. Also they can hold up to tons of power. Over at turbobuick.com there are guys running those rearends in 8-9 seconds cars. So build right and they will last.

Hope this works. Try reading this

http://www.elcaminocentral.com/showthread.php?p=194053&highlight=rear+identify#post194053