Ahhhh, my guess would be that it would be a different block altogether. Possibly something with the same bore/stroke as the LS1. The 2uz block at the ragged edge barely makes 5.65L, and then the piston is drug so far down that the motor runs into oiling issues, hence it being a "race only" application. To make the new motor more public friendly, all of that would hav to be overcome. I would imagine that the transmission flange pattern would be the same, seeing as it hasn't changed in 16 years, but that's a guess as I don't have the motor infront of me yet.
Eric