I used SS springs on my 70 when I built it. With the 30 in tall back tires the car just set too high for me. I used the 2 hole front spring hangers and lowered it that way and it still wasn't enough. I ended up installing a pair of 1 1/2" lowering blocks too. I'm happy with the end result. Lowering blocks will not change the pinion angle but it is also a crutch. Best thing to do is have the springs arched to give you the ride height you want without changing all the factory settings. Its all in what you want to spend and how you want it to perform.