Hey buddy!
I agree with the above, the LSX engines have great heads that can really flow with some port work. That and the light weight is very cool. If it was an all-out race motor I'd lean towards the standard small blocks, but for a 450-500 rwhp n/a deal I like the ls setup.
I would be very curious how he got 550 rwhp n/a; my big blocks never made that much, and although they were not race engines they were pretty stout.
Jody