Ball and trunnion boot replacement

If I were you, I wouldn't use that NOS Mopar boot. It's new (never been used) but it's also old (been sitting around for years). Rubber degrades with age and exposure. Get a new boot from www.oldmoparts.com ; if you're working on any A-body thru '65 the one you need is the one listed for '60-'62 Valiant (Bernbaum doesn't officially support cars made after '62).

The cross-and-roller front U-joint conversion does not involve getting a new transmission; StrokerScamp is teasing you. See here and take note that it has been reported the bolt-up flange part number has changed (or is incorrect in the linked article); it is now 2-2-349.