I went from A TH350 to a TH700R4 with manuel lock out. I came out of a 89 Camero. I has a lower first gear and in overdrive it increased my gas mileage on the highway. I have a s10 and pull a 16' Palm Harbour Boat, I can smoke the tires to no end, the engine puts out about 330HP. I would suggest you putting a Corvette servo in it before you install the tranny and do not put a shift kit in it. It will take the comfort out of the shifts ( real neck jurker), the Corvette servo will give you a good snap. Steve Roy srsv8dime@bellsouth.net