I looked at my 3.54 Rear again. It is actually a Dana 3.54 which came out of a 1968 3/4 ton with a Big Block. engine. I think 4.10 was the fastest ratio ever built for an Eaton housing. The 4.10 are scarce and the 3.54 are even scarcer. Some years ago I read about someone trying to develop a 3.73 gearset for the HO series, but I'm not sure if any of them were ever built. I have a 55.2 GMC 3/4 ton that has 4.57 rears. My plans are to replace both axles with 1/2 ton which was 3.90. There was a 3.08 Dana behind automatics. It is a little too fast for a 3 speed unless you have a good sized motor in front of it.
