Came a across this listing, for the coin the 8" 10 bolt rears are bringing, you can have a 9" WITH the upgraded disc brakes, price seems fair!! Link below
78-88 GM G-Body 9-Inch Rear End Builder
Currie 9-inch rear-ends for 1978 thru 1988 Malibu, El Camino, Monte Carlo, Cutlass, Regal, Grand Prix, and Monte Carlo, G-body vehicles are complete direct bolt-in assemblies offered with a choice of popular differential type, gear ratio, and brake package
www.currieenterprises.com