65 gmc front end upgrade

[duramax55]

hi just got a 65 gmc and wanted to know if you guys simply rebuild the front suspension or replace with something else? noticed mine has torsion bars rather then springs wonder what kind of ride and control that would give? if i keep the front end and rebuilt with lowering spindles? also what kind of power could the original rear end handle or should i put something else in. plan on running a 6 or 6.2 ls in it. Thanks in advance Denis