8" uncompressed x 2.5" ID springs seem to be the standard.
But will they be too short on my '84 if I'm not using the adjustable perches yet?

Does anyone use progressive springs?

Yes - they will be too short. I'd also avoid progressive springs on a track car - you want predictability and firmness. You can use them but it would be like when I was racing on the stock suspension and had to wait for the car to settle every time i made a maneuver.

Thanks Jerry,
I'll look for some 10" static springs.

I have the 10" and now will need to get the 8" because of the mookeeh camber plates I intalled make the car too high and I lost the ride height adjustability. There are other expensive camber plates that don't take away the shock travel. If you are going to race the car eventually, you will want the adjustable spring perch to adjust the front corner ride heights.