Rear Suspension EPS springs:
Left; new springs from Evergreen Performance Systems (EPS). http://www.eps-hane.com/
Right; New spring compared to old spring.

Front mount.

Rear mount.

Since these springs are (1 3/4 wide) narrower that stock (2 1/2) I gained 3/4 between the leaf and the tire. Evergreen came up with that solution years back to allow for larger tires in the rear of their Mustangs.

New height with new springs installed and without 1" lowering blocks. These springs set my car 1 to 1.25 lower than my stock 42 year old springs.
Rear rim size: 17x8 w/5 3/4bs
Rear tire size: 255/40x17
Rear Differential: 9" Versallies 28 spline with disc (detroit locker on it's way)this rearend is 1" wider than the stock Falcon, spring pads were on point.