The numbers are probably Dodge numbers which mean nothing to me. However, most of the New Process had a 6.06 first gear. They could either be a close ratio between 4th and 5th or a wide ratio with a .81 overdrive. If it is an overdrive, someone is probably looking for it. The best way to find out is to put it 5th gear and see if the output turns the same speed or faster than the input. They are tougher than one might think. There were literally hundreds of them behind 409 Chevs that hauled grain from the Texas High Plains to the port in the 60's and they took a lot of abuse and stayed together. I ran a NP541 behind a GMC 370 V8 and grossed 80,000 and never did tear it up.
