I think you cannot deny the cylinder head capability. In the GM catalog they have a new head coming out called the LSX-DR for drag race. It has a 2.25 intake valve and says the head is capable of 430 cfm. There is where the difference is going to be. That will be a fast cylinder filling port. I am ALL IN with the LSX block and that head with 454 inches. That LSX block can be bored to 4.250. I want to go 4.185 and 4.125 stroke for a 454 on pump gas. It will be a torque monster Im sure. BUT I still have a 406 and a 565 old school. They will continue to stay home with me.
In fact the unported L-92 cyl head flows in the 316s at 600 lift with a 4 inch bore. GMPP catalog is only 5 dollars, go get one this engine platform is awesome!