I was just in the garage checking the shock angle on my 56 Chevy. It looks like the angle on the straight axle will be about the same as original GM. I know its apples and oranges. As for stiffness, I plan to go with Chris Alston VariShocks. They are double adjustable and advertised to really help with weight transfer initially, then control rebound as the car planes out. If I ever get this thing to actually run, I'll let you know how it works out!