All I can tell you is what I've witnessed and done myself...I've seen a 440 PUNISH an A833 4 gear to the tune of Upshifts without the use of the clutch. I've seen numerous 5000 RPM Clutch dumps...I myself, have beat the hell outta one and never hurt it...I'm not saying he's Ronnie Sox or anything, but I've ridden with my brother when he's "had a few" and brutally tortured an A833 with a BB Chrysler 440...
I've seen only ONE failure to this day and the driver KNEW full and well about it too.. The front bearing was going bad and he skinned the input shaft. Other than that, I've seen 833's take (for lack of a better term), "Abuse"...ALL of these were 23 Spline units as well. Nobody round here anyways, has the money for the 18 Spline stuff..