This 92 5 speed has a .79 overdrive, combined with the 2.73 rear axle and 28 inch tall tires, it works out to 1550 RPM at 60 MPH. It seems to be doing well on fuel. The front tank is 16.2 gallons, so I can fill that one and see what it does for mileage.
Original EPA was 15-19 and there is no specific figure for the axle ratio. I know Ford went for low revs per mile a while back, about the same time they decided that oil pressure was fine in the mid 30s instead of 60 hot. The mileage seems to suffer significantly with the higher ratio axles. I think it will do pretty good with the old long stroke 300 loafing along at under 1500 RPM at 55 MPH, especially with the port injection and feedback system for good atomization at very low engine speeds. Just drive it like a diesel.
I also read about a lean stumble from slightly too much EGR, which I feel but it's not too bad. Threw some injector cleaner in her and pumped up the tires. The fuel guage doesn't seem to be dropping like a rock so maybe I can hit 20 on the first measured tank.
I'll try to get it running good with the present volume of EGR, then I might try some of the restrictor modifications to the EGR that are supposed to solve driveability problems from day one in some of those trucks, but I would like to leave it alone since the current wisdom is higher EGR for better efficiency, to the point where the stumbling becomes noticeably obnoxious. Restrictors can be easily installed to limit EGR flow, and it is reversible so you can try different sizes and enlatge them intil you get the perfect compromise.
Property taxes less than 20 a year, insurance less than 250 a year, with only 85k on the clock right now its the perfect truck for my occasional use. Heck I can even carry the motorcycle in back or on a rack in the front, LOL.
Now for an aero bed cover, 100% over EPA here I come!
regards
Mech