Getting that rig up to 55-60 is a pipe dream, and no, it won't be comfortable. It will be all over the road, and if anybody else is on the road with you, you'll be a deadly hazard to navigation. Be absolutely sure you rebuild the brakes, steering, and suspension to "factory new" condition before you even consider any sort of gearing upgrade. 2 speed rear axles have two basic operating modes - - - -"slow" and "slower". The 248 with the 2-speed should top out around 45, no matter what you do to it other than swapping to a higher ratio single speed rear end. Then you'll have a really big "Cowboy Cadillac" that will be worthless for carrying the kinds of loads it was designed to haul.
Jerry
