I put a lot of miles on a box-stock 58 Chevy Delray sedan, with a 235, a 3-speed standard shift and a 3.70:1 rear axle. Keeping up with 75 MPH traffic was not a problem, with the standard 14" tires. Now, I know it wasn't a pickup, but the same setup in a truck with somewhat taller tires should work OK, as long as you don't try to haul a bed full of gravel, or something similar.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!