Bruce is correct, when using stock spindles, the OEM camber curve makes the tire lean out at the top when tire is in bump (outside tire in turn). This causes tire to rub. When lowering front you have two options:
(1) Use B-spindle setup (like Bruce) which changes camber curve so tire leans in in bump creating more tire clearance. This setup has two downsides, (a) you have to make changes in tie rod connections to get bump steer corrected, (b) B-spindle pushes wheel hub out by about 1/2-inch so you need to change backspacing to have improve outside tire clearance and to minimize the scrub radius.
(2) Modify stock metric spindles with longer B-body ball joints. This lowers the car an extra 1/2-inch and also results in a chamberr curve almost like the B-spindles. You still have to work on tie rod ends to correct bump steer with this setup, but the wheel hub is in stock location. This setup does have a down side in that the stock top A-arm has some clearance problems now with the down pipe. With the same springs, this setup will result in a 1/2-inch lower front than the B-spindles unless you use dropped B-spindles.
Regarding the rear, lower springs are your only option. One caution regarding lowering the rear, do not lower the rear so much that the front mount for the rear arms is lower than the rear mount. This will not help the already pronounced problem of rear squat under load. If you do have to lower the car so that the rear trailing arm mount is higher than the front, I would modify the rear mount so the connection is the same height as the front. This in conjunction with the increased angle of the upper mount will reduce rear end squat. You need to check your rear instant center to confirm this.
I have modified my rear instant center to add anti-squat and my 60-ft time have been reduced and my control using power has also improved (I do not use air bags). I have less power overstear coming out of a corner.
Just my experience to date. Lots more to learn about setting these cars up.
Deep Enough
Donald McMullin