Truck in question is a 66 Camper Special with the "close ratio" NP 435. Thinking about swapping it out with another that has the super low first gear. I know if I go this route and find one newer than 1967 it will have the 23 spline input shaft and will necessitate a new clutch disc. But
I picked up one walking around one of the wrecking yards last summer while Rick was crushing a load for me. Not sure what diameter it is since I never measured. I like the job partly because I get to do that.