im currently running a 350 trans with 355 gears in rear. took it to a gear shop to have them changed to a better highway gear. the man said he could do me no good. at 70 he figured by a chart that i would be turning 3100 rpm way too high. By putting 308's it would only drop 500 rpm. he then suggested the best thing to do was put an overdrive tranny in it. have any of you run into this? By the way dont plan to be hitting the 70 mph mark often just want myself and my truck to be comfortable. Oh it has a 350 motor.