Try jumping over to the "crashbox" forum. Some of those guys really know their stuff about what will change out for what. 65 MPH is faster than I would want to push that truck without a bunch of upgrades. At least the front end and brakes want to be in first class condition. What I know about the 2 speed rears is that they are slow 6:1 and slower. I think the stock "faster" single speed rear is 5.2:1. Then there's more modern wheels and radials too.
