Before you gear it up to go any faster- - - - -have you done anything to upgrade the brakes and steering? At least do a full rehab of the stock steering- - - -king pins and bushings, drag link, tie rod ends, etc. The straight axle works well on the higher-capacity trucks. Stay FAR away from the various IFS systems which are all based on subcompact car components and are totally inadequate for a full-grown truck. Disc brakes- - - -definitely!

If you're running highway speed anywhere near me and mine, I'll be a lot more comfortable if you can steer and stop, as well as keep up with traffic!
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!