Hay Dalbuie:
With that long bed yours looks like a ¾ ton. Does it have an open driveshaft (with an exposed universal at the back)? I can not quite see it in your photos, but if this is correct look up my tech tip. With a little work you can have a 3.90 gear instead if the original 4.56. I get just over 50 MPH at 2500 with 205 X 15” tires
Additionally once you get that ’55 to ’62 differential you could get a 3.38 gear set from Patrick’s.
