tjscj7s,
The Napco trucks are spring over front and rear, and as you found out your year truck has a narrower set up. The front axel has a taller spring perch welded to the axle and uses 2 u-bolts the same length on one side and 2 differant length on the other other side as that perch is very close to the pumkin. I am not sure of the rear lift bock height for the earleir Napco trucks, but the ones in my '55 2nd series, are 4 inch.
I have also seen some early Dodge 4x4s, and the axle set up, is very simular to the Napcos. You might try, the NAPCO 4x4 sight, very simulr to the Stovebolt sight. The helped me alot with my Napco questions. Good Luck!