I have used them behind 400+ hp strokers with no problems. The one in my car now has had a turn behind the stock 3182bbl, a 402 stroker, a 318mpg motor and now a stout 360 with ported mag headsXE268 cam M1 single plane intake... and it still shifts great and no broken input

The input shaft is hollow but it is bigger diameter so in my opinion it is just as good as the non LU.

I am not causing global warming, I am just trying to hold off a impending Ice Age!