[jumpsoffrock]

My '67 C50 rear end differential was swapped out with a higher geared unit. It came with J15 : 20000-LB. 2 SPEED AXLE 6.5/8.58 RATIO

I bought a lighter duty J13 : 15000-LB. 2 SPEED AXLE 4.86/6.61 RATIO

And installed that diff, with 22.5 tubless tires and the new higher geared diff, it is effectively like a 3.73:1 in a normal car, fairly reasonable.