Fastest ratio was actually 5.43 for the single speed axle, but the chances of finding one are pretty slim. That gear was an option for most Chevrolet 1.5 ton trucks, but came in some school busses and some other odd models. GMCs also used them in the 300-350 series range, but again an option mostly or in some of the odd models. Pretty much any single speed axle from the 40s-50s will probably have 6.17s.
There were a bunch (Timken and Eaton made some) of different axles used in the military trucks, could you get us some pictures of the axle so we can see whether or not its the same type?
Jeff
