[leftybass209]

The bigger issue I see is your sloppy shifting TH400. Find out if its an issue, or if you're just used to modern transmissions. Biggest mistakes I see on this board are people who replace and modify what they want to, and not what they need to, or what's more practical and efficient. It would suck to swap rear gears, then your transmission goes out and needs a rebuild. That money could get you really far into an overdrive where you'll benefit from a few added mpgs AND keep the low gearing if you wanted.