When dealing with early '60s GM rear coils, what's the best way to get 'em down? The only thing I can see is to heat 'em up because they taper at the top and bottom to fit the spring cups.
The best way is to have a spring shop make you a set of shorter springs. I'd check with these guys although someone from Ohio may have a better suggestion. Automotive Spring Service (614) 291-9661 859 Gray St Columbus, OH Back when they used to sell clamps to put on the springs to squeeze a couple of coils together but that isn't the best. You can always do what one of the kids I went to highschool is said to have done and that is put a few cement blocks in the trunk.
For the record I will say that a new set of coils and shorter shocks would be best. But lets say you want to save a few bucks: I know someone is gonna give me the "you can't do that 'cause....." for this but here goes. I chopped a set of rear coils for my Caddy. I cut them down then I heated the end that I cut off and "re-pigtailed" the end so it fit the mount again. Just make it look like it did when you started. Make sure you get shorter shocks so that the coils won't fall out since they are now shorter. I didn't get them and when I would put the car on the lift I could pull the springs out by just tugging on them and I'd have to set them back on the mounts when I put it back down. They never fell out but it would be better to get the shorter shocks. Now here comes the barrage from the peanut gallery about how heat ruins the temper etc. I know it does ruin the spring, but you are only heating the very end and there is a lot of coils left to do the "springing". And if the old timers used to heat them all over and in the middle, then a bit of heat on one end ain't gonna do nothing. Hope that helps you out a bit....Mike.
what are you trying to lower? if it's a full size gm, use intermediate ('a' body) springs. intermediates can use 3rd generation f-body (camaro/firebird) rear coils, cut to fit. however, you will need the upper spring locator from the firebird, it fits in the pocket at the the top and centers the coil.
If you intend to drive it, and dont want trouble . Springs are not all that expensive..Eaton Spring in Detroit will make you what ever you want. And they are very reasonable.
Torch 'em and it will change the temper of the springs and open the likelihood of breaking them in the future - not a good idea. New springs, made to your specs, are always the best way to go. As was said earlier, clamping them was done, but not reccommended. If you want to cut them, use a cut-off wheel and cut them slowly, a little bit at a time, to keep them as cool as possible.