Tex, not a problem. I have done a lot of "paper" modifications to my truck. some of them ran into some serious problems (like trying to fit 40" tires with only my 4" lift, possible, but tons more work that I am willing to do). It is better to do what you are doing that to spend serious money on new rims/tires just to break something in the truck.
I'm not saying it can't be done. There is always a way around it. Question is, are you willing to pay what it costs to do what you want. If you could get your hands on a 2wd Expy then modify the signal from the front wheel speed sensors (probably a $200 box that you would need to splice into the harness), then you would be golden. You try doing the same thing with a 4x4 truck, now you are having to find very specific gear ratios, specific size tires to match up to the gear ratios, the box mentioned above, etc. There are 4x4 trucks that use different size wheels front and rear. Take a look at a lot of the mud boggers. They actually spin the front wheels faster than the rears. This only works because they are on a surface that allows for a lot of slip. Asphalt just doesn't do that for you.
If you want to do this, I'm sure we can make it happen. But, I would tell you to sit down with say a photo editing program and do a rough picture of what you are thinking. that way you have a visual of what you are thinking and we can take things from there. but, a lot of this project is going to revolve around what the specs are on the rig we are starting with.
Im sorry but I have to call you on this. The speed is calculated via the tranny output shaft in my 2000 expy. When programming ECU you have to put in correct gear ratio. My tuner originally put in 3.73's and my speedo was off.
