I have a 31 Model A stock front crossmember in a 32 stock frame.With the frame sitting level and the crossmember in the correct position I am reading 4-1/2 degrees. I've read that 6 to 7 degrees caster is needed for the car to track straight. Do I need to move my crossmember or will the spring/axle/wishbone combination add a couple degrees to it? I am splitting a pair of 37 bones for this.