Rear Springs?

I have Hotchkis 1901R springs in the rear , which are a 1" lowering spring . I needed to keep air in the bags to keep the tires off of the fender lip ( 275-60-15 ) with about an 3/8" to the frame . With rolled fenders they would tuck in .
These are the springs .
View attachment 296514

This is with the old wheels and Hotchkis springs with some air in the bags ( 8psi ) .
View attachment 296510

I like the way your car sits. I'll see if I can round up a pick of my car. It sits way higher in rear
Your front springs are probably 5606. You don't want to lower the front of your car. If anything, raising it would help,but along with that you need to lower the rear. This puts more weight on the rear tires. Having smaller diameter tires on the front than on the back creates a disadvantage right from the start because it creates a situation where the front is lower than the back. I personally like the front to be slightly higher than the back. If we start out this way we don't have to waste so much time moving the front of the car upward during a launch. We can spend more time moving the car forward.

Shocks are critical also. Don't wast your money on single adjustable shocks for the front unless the adjust ability is heavily biased toward rebound. Ridetech has a single adjustable that does this. Don't buy single adjustable shocks that adjust compression and rebound equally. This is what you have on the front now.

It's also important to push the car forward at the right spot. This is accomplished by changing the instant center by changing the angle of the upper rear control arms. This is what pacecarta was talking about when he mentioned the set up he purchased from Baseline Suspension. Unlike what pacecarta said,I don't want to see any separation between the rear fender wells and the rear tires during launch as this is counter productive to weight transfer and evidence that we are not pushing the car forward at the right/most efficient spot.

If you want to see what a drastic difference weight transfer and weight on the rear tires makes put as many heavy items as you can find in your trunk. Doing this will lower the rear and raise the front.
That's good info to know! I'll have to look into the instant center concept a bit more. Could traction be achieved with better different spring / shock combo?