43longtime

I have a couple of questions.
I have been working on my 1983 Camaro z28 that I am making into a race car. I was wondering if anyone has any Idea what the weight of the rear end is so I can pick the right size shocks out. The 4 link I am going to use is the competition engineering one from summit racing. One other thing too how do you know what size frame to get like the 24in 26in 28in does that have to do with the size of tire being put into the car or something else.

Thanks

Chris

radical82

Best way to determine frame rail width and rear end width is to put in place the tires and wheels you are going to run so they have adequate clearance to the outside of the fenders. Measure the distance between the tires, allow for 1" to 2" of clearance for each tire on the inside and this will be the width of the rails. For your rear end width, measure the distance between the wheels where the mount to the rear axle, this will be your flange to flange width for the rear end....

Weight of the springs is best determined with the car all mocked up, including engine and trans, the driver or equivelant weight in the seat, and the car on a set of wheel scales....then a call to your favorite spring company to get the correct springs. Don't scratch up the springs that CE sends, if they still look new you can exchange them.

43longtime

Thank you for the fast response. I Called up summit racing and they told me that I could trade the springs in as long as I didn't mount them to the car. As for figuring out what size frame rail I am going to take your advise and set the tires in there and measure everything.

Thanks.
Chris

AlkyIROC

I run 130 pound springs and when I did my back half, I set my frame rails on 24" centers.

https://www.thirdgen.org/forums/fabr...k+half+project

43longtime

I ordered the frame rails today from summit and I went with the 24 inch frame rail like you did. Thanks for the thread I am looking threw it know. I will start my own when I get a chance to take some more pictures.

Thanks
Chris

AlkyIROC

I originally had 150 pound springs but they were too heavy. The springs just need to hold up the vehicle and allow enough travel when adjusted to ride height. The 150 pound springs didn't compress enough. The shocks do all the work and if the springs are too stiff, the shocks can't do their job.

My back half wasn't a third gen specific kit. The frame rails were just generic so I was able to position them wherever I wanted.

43longtime

Yeah I noticed you welded all of them up separate. I ordered the kit its easier for me. The springs I ordered with my kit where 125 lb So maybe they will just work fine I hope so don't want to have to send them back and get different ones but you do what you got to do.

radical82

You're welcome...always easier to start building when you have dimensions for what will fit... Besides, I always set the tires in place first cuz I'm lousy at guessing!!!!!

AlkyIROC

125 pound springs will do fine. I think you could go as low as 110 and still have enough travel in the shocks.