This article will be to inform the '78-'88 a & g-body owner of what aftermarket springs are available to upgrade to when the originals wear out, & greater handling or load carrying capability is desired. Mostly, this information will save the consumer from spending needlessly on overpriced aftermarket "pretty boy" springs like Eibach, Hotchkis, and Edelbrock.
"When you think about spring rates, your only considering the spring by itself. If the front end of a car weighs 2000 pounds let's say, obviously the springs will have to hold up that much weight. If you have two springs, one with a low spring rate and one with a high spring rate, the low rate spring will be longer (on its own) than the higher spring rate spring. If the suspension compresses the spring to 5 inches long when sitting on the ground, the lower rate spring will have been compressed farther because of its lower strength.
A 200 pound/inch spring will have to be compressed 6 inches to hold up 1200 pounds.
A 400 pound/inch spring will have to be compressed 3 inches to hold up 1200 pounds.
That is why a higher rate spring is shorter and the resulting supension motion is reduced. Drag racing front springs are very light and very long so the suspension will rise to the end of its travel. If a short, strong spring was used, the motion would be greatly reduced, limiting weight transfer."
Front Springs in the g-body support a great amount of weight, given the weight of V8's, turbo V6's with intercoolers, and even the little V6's.
|Mfgr.||PN#||wire diam.||load height||rate|
|Moog||5662||0.74||10.75||706 in/lbs||Eibach||  Pro Kit|| || ||660 in/lbs|
Other interesting notes on front springs
The aftermarket springs companies sell their products at prices approximately doubling that of retail for Moog springs. To give an example, My 4 Moogs for an '86 Monte Carlo (part numbers for other cars, however heheh) cost me $114.xx out the door. Jegs wants $264.99 for Edelbrocks G-body set. Quite simply, if you believe that Eibach's springs are magically a "matched set" which is going to provide superior handling over "off the shelf" Moogs which are trimmed slightly, or you think that Eibachs are better quality, you've just become a victim of their advertising. What you end up paying for is their advertisement budget and colorful powedercoating (Moogs are powdercoated black.) The Moog part numbers above should cross over to TRW / Federal Mogul part numbers at a competent parts counter if you're not able to find Moog carried locally to you.
The amount of drop from a given spring is going to vary greatly because of worn out original springs, options on a car, modifications (fiberglass hood, aluminum heads?) and the original weight of the vehicle over the front suspension. If a spring doesn't lower the car adequately, more can be cut off, but 'tis better to cut too little than to cut too much. After removing some spring material, it is a needed step to create a "seat" at the end of the spring by heating and bending the end of the coil. The reason for this is that the flat face of a spring is a better foundation to sit against the frame than is a pointed end!
If you're looking to road race a g-body, aftermarket companies are making springs in excess of 1000in/lbs for the third generation f-bodies which will fit g-bodies. Also, to be noted is that the above spring numbers are in no way a comprehensive list of PN#'s that will fit g-bodies. As soon as I have access to a Moog Catalog, I'll post more info.
|Mfgr.||PN#||ride height in g-body||trimmable?|
|Moog||CC651||stock to 1/2" higher||no|
|Moog||CC635||stock to 1/2" higher||yes|
The CC651 is the Moog recommended "Cargo Coil" for g-bodies. This means a variable rate spring that holds loads very well without the car bottoming out. After carrying in a trunk a SBC 350 w/ heads + a 700-R4, using CC635's at the time I'd say they do their job admirably!
The CC635 is the Moog recommended "Cargo Coil" for '82-'00 f-bodies (Camaro Firebird) This spring will fit a g-body with the rubber upper spring isolator from the '82-'00 f-bodies. Apparently GM still carries these, they are in any junkyard that has an '82-'00 f-body, and Jegs apparently has poly ones. In most F41 g-bodies, there is a small metal "cup" bolted to the frame, opening downwards. This cup holds the rubber isolator in place nicely, and lessens the likelihood of the spring coming out, but unless you go airborne, this is not a concern.
The reason why the f-body spring is listed here is because it is firmer than the g-body spring as well as having a single pigtail configuration. The g-body springs have a pigtail on top and bottom, meaning that if you want to lower the car, you're out of luck. With the f-body springs, only the bottom is pigtailed (which seats on the rear axle) but the top can be trimmed to lower the car.
The Moog part numbers above should cross over to TRW / Federal Mogul part numbers at a competent parts counter.
lower rear trailing arms in the following are identical:
lower front control arms in the following are not identical but very similar:
upper front control arms in the following are identical: