[Richard]

The 6L90 in the ZL1 came with a 32 spline output, it is available. A 32 spline female input gear is available. As my motor and trans is from a ZL1, used the Advance kit and it bolted together with a bit of trimming on the output shaft and 32 spline input to t-case. Understand wanting to keep stock stuff intact, do this myself. Had to really think about whether I would have the time, resources or ability in the future to return my truck to stock. For me the answer is no. I still have my stock transfercase as I had my dad's original case bored for the larger female input bearing. Wanted to keep mine for spare parts, do not see it ever going back in the truck. There are some pictures of the install in my build thread. Back of the 6L90 transmission needs two plugs and a seal installed once the tailhousing is removed to hold the oil in it. The adapter runs dry.