I presently have a '84 MCI9 with a 8V71 that I recently replaced with a 8V71T with 80 injectors. This produces approx. 385HP and I will say that it does run nice down the road. It has a 5 speed manual transmission and gets approx 5.5-6.0 MPG. My rear end recently went out and I was wondering if anyone had any experience of running different rear end ratios to increase mileage? I drive 35K miles a year and with $3/gallon fuel I'm looking for any improvements I can find!