TNTS79 hit the nail on the head. Front suspension travel is the key. One of the biggest improvements you can make to your G-body is to the FRONT suspension. Look at the picture below of one of my old stock upper A-arms. This is the single most important modification I made to my car for traction back in the "old days" of my car. This is one of my best kept secrets and this is the first time I'm ever sharing it.
Here is my old setup that I ran low 9's with and wheelies on the street:
Modified upper A-arms as shown in the pic below
Comp Engineering 3-way front shocks
QA1 single adjustable rear shocks (Double adjustable would have been even better)
Stock front springs
Stock rear springs
TNT Raceshop double adjustable rear upper control arms
TNT Raceshop tubular rear lower control arms
That's it. Very simple and low buck, but very effective for any G-body running high 8's and up.