If you are using the '55 housing there is no need to weld anything. The welding is for when one puts the later pumpkin in a torque tube housing.
Ideally, you need the '55 first springs. The mounting holes in the '53 springs are forward of the center of the springs. The '55.1 springs have the hole almost centered. I have read of people drilling new mounting holes and I have read of people mounting the springs reversed. The latter will move the axles aft of the stock location.
