maybe in a 1500 but i rode in a 8.1 in a duellie with an big exhaust kit and a few other goodies and i got too tell ya ,when i had a stock 4.8 in my truck it would of walked it ,it felt doggy to me.but also consider i believe that thay probably weigh quite a bit more ,im not sure how much.i think id still go 6.0 especially cause everyone on her mods the crap out of them and you can get alot of hands on expierience from us guys, were im not so sure i hear much 8.1 talk.just a thought
mods:2004 sierra ext sb,20s ,big brake kit w,hawk pads,air bagged,2006 6.0 lq4 swap,vortec supercharged10psi, air to water intercooled w/ dual electric fans on it ,snow meth injection kit,60lbers, e-fans ,big radiator swap ,cam 218 /222 548/550 comp .hardened prs .1.85 comp roller rockers ,guideplates ,crane double springs,trans 4l65e built .pacesetter l/ts true duals w/x pipe and magnaflows,14 bolt rearend swap ,3.73s,aroemotive fuel pump system w/elec.fuel controller and bypass regulator a/n fittings, taylor 10.5s interceptor gauge,aem w/b a/f ,autometer boost/vac NELSON 93 OCTANE TUNED .