4L80 Question

[Gtrpunk23]

I read somewhere on here that someone mentioned using a 99 and up 4l80...for what reason I dont recall other than the bellhousing bolt at 12 oclock.. My dad does this stuff for a living for the last 30 years and non of the differences seem to be of much significance other than maybe some cooling advantages. Someone please fill me in on what it is I don't see here. Or am I delerious?