I rebuilt a 235 from a 55 car and put it in my 62 half ton , I also went to a t-5 from a 92 s-10. the truck is running great but I still get bad gas milage 12 ish mpg. I took it on a long trip this week to go fishing (240 miles round trip) Thats about 60 in gas and it was a beating . I dont have a tach but at about 60-65 it was reving pretty high. My question is can I do the rear end gear swap my self and if so what do I look for? I am not concerned about power I want to cruise comfortably and get much better gas milag. Thanks fellow bolters !