From what I have read, you should be good with an engine later than '01. I believe the 6.0 engines in the 99 and 00 trucks have the longer crank. Starting sometime in 01 they went to the shorter crank.

My 6.0 came from a 99 Silverado and it did have the longer crank. So bolting it up to an older 4L60E was not an issue for me.