Looking for info on '72 swb rear axle setup???

['72MotherTrucker]

I have a '72 swb and I thought that the rear would be leafspings, but there is a coil sping setup. Is that stock? Is it functional or is swapping in some other pieces, parts a better option??? Any help and suggestions are much appreciated, I just got the truck for $225 b/c original owner couldn't keep up on the insurance, and the frame needs some welding near the rear axle. (OHIO RUST), but the thing runs/drives nicly for that issue. I also was wondering about how you find the rear gear ratio?? Door code, axle tag, where do I look???

[bagged92]

Coil spring is normal. The rear axle ration can be identified by numbers on the housing on some models, if not you can spin the tire one full rotation and compare that to how many times the driveshaft goes around, and that will give you a close estimate.