Newbie rear susp question

[Chassisworks]

Originally Posted by Vince@MSperfab

Carl, could one redrill the leaf spring perch mounting plate to compensate for the rear end offset? Or is the offset built into the upper mounting bars too.

All GM cars seem to have this problem. More tire space on one side.

Hey Vince,
The OP has a GTO so it came stock with a triangulated 4-link and coil springs but the instructions DETON8R posted are for our Camaro system which has a pretty comprehensive install guide. IF the car were a Camaro and it had the leaf plates, my answer would be NO, do not redrill. Just make the adjustments with the bars. If it were a leaf spring car then just buy new leafs. If that doesn't fix it then something is bent.

Regarding lots of GM cars being offset to one side; there is a reason. First, leaf springs suck, especially the ones built 50 years ago. Second, A and G body cars with stock 4-links are going to be prone to misalignment.

Here's why.

The stock lower arm's I-beam construction is designed to twist so as to prevent suspension bind. The driver side lower sees the most abuse. After a while it has a permanent twist which makes it slightly shorter and the car rear-steers left. The hot ticket back in the day was to swap it to the right side. (Then the car would go right until you had sufficiently damaged the other arm!)

The upper control arm crossmember is a relatively weak point in the system and prone to bending. This is why we recommend installing our control arm support braces on cars with decent power.

[Vince@Meanstreets]

Thanks for the reply, my post was supposed to start with. On a Camaro....sorry for that.

Great info