It would be a crying shame to butcher up a nice well-restored truck with all the Rube Goldberg junk you're proposing. A T-5 is a puny weak sister transmission compared to the SM-420, and there are differentials available to swap your gear ratio to 4.10 without spoiling the original appearance and hauling capacity of the truck. There are far too many cobbled-up "upgraded" trucks already, most of which never actually get back on the road again. With a 4.10 rear end and some original-height tires, you'll be able to run 60 MPH all day. Any faster is just plain unsafe without lots of so-called steering and suspension "upgrades".
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!
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