[comptiger5000]

I originally thought the same about mounting the T56 to a t-case. However, it's apparently been done before with adapter plates and/or a different tailcone.

A stock T56 is rated for 400 - 450 lb. ft. of torque, my engine puts out 345. So that even leaves a little room for growth, especially if I used a beefier aftermarket T56 rated for more torque. For around town mileage, if I were going to do anything, I'd like to ditch the auto tranny. The t56 would give me that, and a good ratio spread. I could also do an NV3550 or something + a GV. Also, I know that I can get gears for both my D44a rear and D30 front in 3.08, 3.55, 3.73, 3.92, 4.10, 4.56, 4.88, and maybe 1 or 2 other steps.

As far as the tire size, the purpose of the slightly larger tires (about 3.8% taller) wasn't to get the RPM down. That's just a bonus effect. Plus, they're only a little heavier. (31lb for current rear tires, unsure of fronts, 33 or 35 lb for planned new tires, depending on which I get, either Toyo Open Country A/T or Firestone Destination A/T). The weight hurts mostly around town anyway, and the mileage is so hopelessly crappy around town, I don't think it would make more than 0.1 mpg difference.

The only aero mods I have planned for now are some not-too-heavy skid plates to clean up the underbody air flow a bit, and offer some protection down there. Otherwise, I plan to do it all with gearing and engine mods (better injectors are said to help, and about $140).

Bone stock, I was able to average 19.2 mpg last weekend running on the highway (no trucks) at 65mph average, including 2 miles of stop and go traffic, with the A/C on the whole time, and with some rain.