old mate down here. Alan Humphris (bless his soul) never had anything balanced, even under LVVTA/LT400 rules. just prepared the job, set in lathe, and welded to speed. he done hundreds of race car d/shafts with no complaints regarding vibrations........... and yes to the naysayers, real fucken racers who knew balancing(if needed) was 0.1-1 second a lap, proper oldschool clever and fast racers