I cant verify if the wings are the same but I im 90% sure the LS mounts shorter than the sc/supra so you would need to re-position the mounts a bit farther out. Check out hypronet's LS400 Turbo thread.. he has lots of pics that show exactly what needs to be modified.
I looked into the "guts" swap and it also wont work. The LS clock is a different size so the only way to make it fit is to make some mounts and swap. Shouldn;t take more than a few hours with the right tools.
