Mike,
My 52 uses the original rear springs, although they are mounted below the axle for lowering. The previous owner did this work and near as I can tell he fabbed his own lower spring pad/shock mount. As far as I know the rear end is a 10 bolt from a Nova[not sure what year]. I imagine you could mount the springs like stock by making your own upper pad/shock mount and using proper sized U bolts. Just make sure you center the wheels in the fenders.

Malcolm1943, if it ain't broke, you aren't pushing it hard enough!