7.5 garbage, in the Malibu's, and 1979 El Camino's. The biggest gear available is 4.56 and the rest of the housing/axles is still to weak to race seriously. I have both, but the 1980 Malibu now has a 9" ford in it.
YOU COULD USE A 10 BOLT FROM A 86-87 GRAND NATIONAL,IT HAS A 8.5 RING GEAR.I USE ONE IN MY SS MONTE CARLO BUT I CHANGED TO 33 SPLINE MOSER AXLE'S AND SPOOL WITH C-CLIP ELIMINATORS.