The stock upper control arm isn't adjustable. It also might be the panhard bar. The stick one is not adjustable and when you lower the car it pushes the rear axle towards the driver side. You can measure it using the fenders and the tires. Replacing the lower control arms helps with wheel hop dramatically. It could be a combination of all. If you get new lower control arms get adjustable or else you'll need relocation brackets for them since you're lowered.
chevy runs deep, Don't step in chevy!
289 - Holley 4150 570cfm; Performer intake; mild cam; MSD HEI; 302 heads; Roller Tips; Hedman Tri-Y headers; H-pipe w/Flowmaster 40's; 9 in posi 3.50; 205/50-17F; 225/50-17R.