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I just replaced my rear spring with a composite one and it seemed to me the rear was too high despite using longer bolts.
Taking advice from folks here, I loosened everything up and loaded the rear with 400 lbs of iron. I drove around with it a bit and then tightened things up.
Redvette - The 1/2 short on each side appears to have the same end design with the hole and bushing cup, all 1/2 inch inward. If that makes sense. On the spacer, I called Van Steel to double check that and the rep confirmed that the spacer goes below the spring. Right now front to back stance is close but I have to get out and drive it then make an adjustment, most likely.
Interesting. So, this inspired me to go out to my garage and take pictures. My 9 year old VBP spring has the spacer on top. Came that way taped from them. Half shafts are level with 8” bolts.
Car isn’t slammed and I have clearance from top of tires to lip. Since the halfshafts are level now, the only way to get body lower would be to mount the differential higher.
Post some pics of the spring and bolts. I assume you have tightened the nut to draw everything down?
The spring came from Zip Corvette a 340lbs/inch
The only weird thing I noticed was my carrier cover. The spring is only supposed to work with a cover that uses 9/16 bolts. Mine are 5/8. The U-joint on the driveshaft is an adapter U-joint stepping up one size. Dunno if that makes any difference.
The spring fit perfectly. But maybe located ...lower ?
Last edited by DorianC3; Mar 17, 2020 at 01:35 PM.
I had the exact same issue with my 1968 after getting the differential rebuilt at a local Chevy dealer. They used shorter bolts in place of the original bolts that were on the car and this lifted my rear end up way too high.
At a Corvettes@Carlisle I met a guy from VBP who was able to instantly tell me the problem without even looking at the Corvette. He looked and said that my bolts were too short at the ends of the rear spring. He said it happens all the time and the solution was a pair of longer bolts. I bought them from him and they solved the issue for me.
Something is wrong and longer bolts will not solve the issue.
Look at the angle of your half shafts.
With the weight of the car on the suspension with the tires on the ground, your half shafts should be level to the ground.
Yours are not and adding longer bolts like you did is only masking a problem.
Go back to the original length spring bolts and correct what is wrong.
As mentioned earlier, there are some aftermarket composite springs that will not allow you to get the proper ride height.
I would start checking everything again and maybe replace that new spring.
Last edited by OldCarBum; Mar 17, 2020 at 02:35 PM.
Something is wrong and longer bolts will not solve the issue.
Look at the angle of your half shafts.
With the weight of the car on the suspension with the tires on the ground, your half shafts should be level to the ground.
Yours are not and adding longer bolts like you did is only masking a problem.
Go back to the original length spring bolts and correct what is wrong.
As mentioned earlier, there are some aftermarket composite springs that will not allow you to get the proper ride height.
I would start checking everything again and maybe replace that new spring.
Longer bolts will solve the issue. It is a known issue with the TRW design rear springs. Had the same issue with my '75 and had to use C4 bolts to get the rear end down. They have too much arch. The VBP designs springs are better but Vette Brakes is now out of business.
Also look at the longer bolts and nuts you have added and notice they already extend lower than the lip of the wheel.
If you were to have a flat tire or blow out the spring bolt and nut would dig into the pavement.
At any speed especially at highway speeds it could cause you to loose control and cause major damage to you, your car and maybe some one else around you.
Adding longer bolts and not taking care of the problem will only add to the safety issue.
Last edited by OldCarBum; Mar 17, 2020 at 03:11 PM.
You realize that composite springs never sag they just break. Now to fix your problem correctly get the right springs and not composite. Look up Duntov Motors. They race C3s and are at the top of there game they will not use composite springs. If your hauling *** down the freeway and your rear spring breaks what do you think will happen next? And just so you know they do not work better than the correct stock ones
You realize that composite springs never sag they just break. Now to fix your problem correctly get the right springs and not composite. Look up Duntov Motors. They race C3s and are at the top of there game they will not use composite springs. If your hauling *** down the freeway and your rear spring breaks what do you think will happen next? And just so you know they do not work better than the correct stock ones
What about the bias ply tires that originally came on the car?
With longer bolts, the bolt head & end of spring will still be where they are, relative to the tire/wheel. But, the other end of the bolts (and T/A housing) will move upward, as the body moves downward to lessen the gap over the wheel. You should know that there is a 'multiplier' effect, such that you only need to add bolt length of one-half the amount you wish the body to drop. So, a one-inch longer bolt should allow the body to drop about 2 inches.
Last edited by 7T1vette; Mar 17, 2020 at 03:16 PM.
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Originally Posted by DorianC3
If that solves my issue I am game.
I have the same problem...initially about 2 inches higher in the back after replacing front and rear springs (has settled only maybe 1/2 inch in 600 miles). However not a composite in the rear but std 9 leaf. I also tried the longer bolts but did not like how low to the ground and close to the inner rim edge they ended up. As far as the axle shaft angles that should improve as the car body is lowered. Doesn't seem to me like anything else is wrong but perhaps that your new rear spring might be too much curve and stiffness for the car.
Let's see what the experts say.
Last edited by Redvette2; Apr 22, 2020 at 03:33 PM.
Reason: Leaf was 9 leaf.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Butt is too high still
. Now to fix your problem correctly get the right springs and not composite. Look up Duntov Motors. They race C3s and are at the top of there game they will not use composite springs. If your hauling *** down the freeway and your rear spring breaks what do you think will happen next? And just so you know they do not work better than the correct stock ones 
