My Ranger is a '93, 4.0L 5spd with 3.73 gears, and 33x12.5's.
That being said, Going down the freeway one night (trying to catch up to my cousin who was up ahead of me, he skipped the rest area, and I didn't) I got the speedo to 85, an when you factor in the tires, that puts it about 93-95mph or so.
I have the tires balanced with BBgun BB's (if any of you have heard of that, it really does work) and at that speed, it was smooth as glass. No death wobble, no tire wobble, nothing, just smoothness.
I'm not saying it is any more legal, but I went half an hour without seeing another car going my direction, on a 3/4 lane Freeway (I-90), at the time that I went this speed. It is one of the FEW times I've had it over 80.