I have Z/28 front springs in the car. It came with 4 leaf springs in the rear, and Big block springs up front. I did not like the jacked up front end so I changed them. The coil spring number is 6308 by Moog. The wheels are 16 X 8 Vintage Wheel Works V45s. The tires are Nexen 621s in 225 50 16, and 245 50 16. I went to a lot of trouble to research this ride height. I owned several 69 Z/28s and they were orginally this height. I owned one brand new in 69. The ride is a little harder with these tires but the suspension is firm on cornering. Make sure you follow the AIM when mounting the springs so the height is equal on all four corners. With the 4.5 backspace you will get the odd rub up front but very minor. Hope this helps