A hospital I worked at in Maine in 2002 had a new 01 Chevy PU with the 8.1/Allison tranny...it breaks down to a 496cu.
I will say, it was, and still is the fastest most powerful stock gas (and diesel for that matter) PU I have ever driven.
Not that you care to know....but I'd take it out on a daily basis just to go out and lay down some INSANE posi strips around Bar Harbor....and feel the rush of the "plastered in the seat acceleration" and HEALTHY shifts.
I did this for nearly 2 years with that thing, and never had any issues....it took the abuse like a typical Chevy. And I know I wasn't the only employee that took it out for a beating either.