My buddy has a nbs vortec max. Hes arguing that his truck has the same tranny as mine. I dont think they came with 6 speeds, and if it did, maybe a smaller size 6L80? I need some facts to back me up.

The 6L80/90 is definitely not an Allison. The VortecMAX now comes with the 6L80 like the Denali and Escalade according to GM's website.

My truck doesnt have an Allison, I think you answered my question, the Vmax's DO have a 6 speed then.

yes the newer ones do

my wifes g8 has the same tranny

Depending on the year, he could have a 4L80e also.