I have a 1990 GT that I have had 3 sets of springs on now. I bought the vehicle as a roller and it had the stock GT springs with those turn in spring booster knuckles. Anyway they went in the garbage, and I installed Eibach Prokit front for 1 - 1.5 drop and sportline for 1.5-2" drop because the added weight of the big block I WAS PLANNING on putting in would have made it lower. Anyway I did a 306 instead and needless to say found out that the sportline springs only look good and are usless for any weight transfer. So I replaced them with 4 cylinder springs. They are soft and have great weight transfer but the car still sits lower in the rear with 4 cyl sprigs than the front with the Eibach Prokit....weird? Im currently running 18"s on it now and have clearenced the rear lip to keep tire from bitting over bumps but the rear is still too low. Nothing looks out of whack back there at all that I can see. I also have UPR solid lowers and MM double adjustable uppers with Lakewood 50/50's. Has anyone ever seen or heard of 4 cyl springs being this low???? I thought they were taller but softer than GT springs which is why it is a good cheap swap because the ride height stays the same but launches better. ....I know control arm adjustments are made for pinion angle so what the balls mahoney do I do about correcting ride height in the back????? Im at a loss but need to get this adressed.