4.56 gears 4-speed?

You can't get tires anywhere near that tall under a Dart without tubbing it or jacking it way off the ground. Mine were 225 x 75 x 15 before I put the 17's on but they did not change much. The 15s were 28.3 and come very close to the fronts of the fender cutouts, so there's not much room left.

So 4.56, with let's assume 28.5" tires would give you all of (there's about 5 gazillian of these on the www)

70 mph would be 3763

60 would be 3226


My car, before I tore it apart had 3.7X rear gear, so a 28.3" tire at 70mph was still 3100. You have to fudge a bit for the converter. The 17s were actually a bit smaller and added a bit more RPM, I think it ran closer to 3300 at 70

I would NOT want more RPM, and I don't go on what you would call "long trips"