i've got a 99 LQ4 block which w/ the factory bottom end can only bolt up to the 4l80....is it possible to change the crank over to one out of a 2001 crank/rear main/rear cover to bolt the motor up to a different tranny?

 

Yes you can change the crank with no problem.

 

probably be easier to get a used 4L80 and just use that, no?

 

not what i wanna do w/ the project...i wanna stay w/ a std tranny & wanna go t56...even though 4l80 would probably be the better route to go for more power/track times i love bangin gears

 

Pretty sure the standard will bolt up to the longer cranked 6.0's, I know the 80 will