[Blue Streak 21]

I understand what your saying. I'm sure an LSX swap will cause all kinds of issues if you want to race the car in a SCCA or other serious series. No one likes a non-standard motor swap. The series I'm thinking of running only has two classes, vintage and contemporary. They have no other classes, and restrictions are minimal.
The '99 to '02 LS1 makes 325 hp at the crank, so it might not cause all that much difficulty for the ST class. I'm sure it can be mod'ed to be 320 hp at the rear wheels. It's the weight savings that I like the most.
I have only just begun to research the possibility. There are many varaibles that need to be considered before I go down this path. The mounts would need to be relocated, and I'd need to make sure the center of gravity of the motor would be similar to where the current 5.0 l sits. I like the balance of the car right now, so I'd want it to stay the same. The engine and all accessories need to fit between the frame rails, and that is always simplier said than done.