Ditto on the taller tires. Back in the days, my 70 Challenger was running a 4.10 dana w/auto. Was my daily drive for two years, travelling every weekend from MD to VA on I-95; wasn't too bad. Had L70s x 15 tires in rear (yes, L70s for those old enough to remember; Hijackers were maxed out at 150 psi to prevent occasional fender rubs). The other 70 had a 4.56 dana (4-sp w/L60s x 15) which was almost unbearable to drive, again on I-95. Had to leave around 1:00am to prevent any traffic tie-ups and truckers from running me over in the slow lane. Drove the minimum 45 mph speed limit the majority of the time, on occasion up to 55. Took about ~4-5 vice ~2.5 hrs for the other Challenger. As someone previously mentioned, stop-light-to-stop light was the fun part with the 4.56's.