I need advice on rear coil sprins

[KevC20]

I am redoing the suspension on my 71 Cheyenne LB c/20(sb 350) and went to rock auto to buy rear coil springs. There are several to choose from, constant ,variable pitch, professional... and then standard or heavy duty. Not sure what is stock for this truck.

I looked under the truck and it doesn't look like they are "variable" as the springs look evenly spaced. There is about 5 or 6 coils. This truck did come with the "auxiliary" leaf but it is not installed.

Any advise would be greatly appreciated.
Going to watch the game --roll tide!

[sick472]

I feel the pain that you may be about to go through as automotive springs can be a real buggar to get spec'd and spec'd right. I would start with Eaton Detroit Spring's phone number. They have 4 styles listed for your truck with the actual weights listed too. That weight may be all you need to determine what you have, but I have found them to be pretty helpful in determining what you have on your truck and what might happen to your ride height if you change styles. Go here...

http://www.eatondetroitspring.com/find/

and fill out the search info to see what they offer along with the spring weights, then give them a call and talk springs. They seem to be open with the specific spring data (like # and diameter of coils, diameter of the steel, overall unloaded height and so on). Even if you do not buy from them, you will likely learn something useful. Keep in mind that springs on any car can be a lesson in patience AND opening your wallet. It took 2 sets of rear springs and a set of front spacers for a recent F@rd project before I got the ride and height the way I wanted. Also, new springs will ride higher than your old wore out springs. Good Luck!

[KevC20]

I will contact them and try to narrow it down. I was just trying to bring it back to the stock ride. I have been reading some of the archive posts and seems a lot of variable pitch coils were used or replaced because of a "smoother" ride. I'm not too worried about that but I want to make sure it can handle a load as this truck is used for occasional hauling.

Thanks for the reply!

[FirstOwner69]

I'm almost certain that the rear springs in my '69 3/4 ton were referred to as variable rate in the advertising materials when the truck was new. The ads touted them as improving ride quality when the truck was not loaded. I think that was the first time I ever heard of variable rate springs. A picture of one of my original rear springs is below.

If you click on the "info" tabs on the Rock Auto listings, you'll get all the specs for each spring regarding load capacity, etc. I have no idea which is closest to factory specs.

[Ironangel]

Since you have the C/20 your going to want the heavy duty 3/4ton springs...Compare them to LMC's springs...

[KevC20]

After reading up on this it seems both can be used (constant and variable). I will be going with the constant heavy duty as this seems like what is on there now. I will let you know how the height changes ,if any, once they are on.
Thanks for all the input!