I just bought a 7.3. It's on 38.5 Baja claws which are worn out. When I bought the guy selling it said it was regeared but didn't know what years were in it as he was the 3rd owner. How can I tell what's in it? Also I am putting new wheels and tires on it. 37x13.50x20, what gears should I have in it? I just bought a 6000lbs boat. I want to tow but still be able to drive down the highway at decent speed. Right now it will rip a house down but 2000 rpm around 65? Hard to tell because it's not recalibrated for the tires.