want to lower the rear of 57 chevy truck

Hey guys, ive got a 57 chevy pickup that i want to lower the rear end some. Sits alot higher than the front. Heres the kicker, its sitting on a 67-72 pickup frame and from what ive been told not that long ago it had lowered springs installed in the rear. Anybody ever use lowering blocks on trailering arms before? Any suggestions wud b greatly appreciated