What do you want to know about the 10 speed Roadranger? The OD ratio is 0.80, and the RPM drop when shifting at about 2300 is 400-500 rpm, just right for a working truck.
I have several of them, including one in my project truck with 4-53T.
Be careful not to get to old of a Dana 70. The real old ones have 1/2" pinion offset and gears are not available faster than 4.56 or 4.11, I forget. The newer Dana 70's have 5/8" pinion offset and gears are available down to 3.54.
You should check out my pictures on the link below, there are a lot of them, and you should probably look at most of them. What you are now talking about is what I have done to my 48 two ton truck, 4-53 Detroit, Roadranger RTO6610, Dana 70.
Grigg
