I beat the holy hell out of a freshly rebuilt M22 with my Bisschop motor, it took 4 years of spirited street driving. I have laid down about 40 12 second passes and many, many mulitple gear burnouts.
I bent the tailshaft and wasted the Italian gears ! Plus 3 clutches. LOL
Last year I put a really nice custom made Supercase M22 with the 2.52 first gear ratio in my 70 Judge. It also has that beefy gusseted tailhousing.
It's holding up just fine.
It's not easy being dedicated to 4 speeds but they sure are fun to drive