I had a 6V-53 in a '67 7500. You may have a point as I maybe just favor a diesel in general, but both engines required a lot of shifting, especially when fully loaded and up and down hills. I didn't mid tho as I always liked shifting. I guess a 6-71 would have been the answer for sure.
Do you remember what the feed store 637 truck had for a trans?
Bill
