As JB mentioned...Moog makes many coil springs that can be used. A couple years ago I found a chart online that showed specifications of many springs that could be used on 73-77 Chevelle/Malibu & Lagunas. This weekend I'll do a little searching online to see if I can find it again. You may want to consider rear cargo coil springs. I used Moog cc507 on my 4250 lbs '76 with Edelbrock shocks & 1 inch rear sway bar. With this combo...I have yet to experience any wheel hop with reduced body roll & provides a nice comfortable ride with ride height dropping to 26 inches with a trunk load of groceries. Normal ride height in the rear with a full tank of fuel is 26.5 inches from the center of the wheel well lip. My front ride height is at 26 inches from the wheel well with Moog 590 coil springs & 1 1/4 inch front sway bar. From what I have learned. Cargo springs are made to become stiffer when applying force or weight to retain factory ride height without compromising ride quality. I should also mention that Hope this info helps.
Last edited by LSANTI76 on Thu Jan 03, 2013 8:41 am; edited 1 time in total (Reason for editing : Added weight of car & sway bar info)