Mark,
International also used the 6 bolt patern up through the 90's. Isuzu NPR rear axle is the same bolt pattern but you have to change the studs to american thread. The gas 5.7 ones have 5.38 gears in them. There are no 2 speeds in isuzu trucks though. That is what I am running in my 57. If you want a measurement on the with I can get you one. I could measure my 59 GMC and see how close it is.
Shane
