Direct injection and high compression made it more tunable than any gas engines, other than BMW F1's, have ever been. It's like tuning diesels. I had an article about it making over 800 HP without any adders. They claim the block is 1500 + HP reliable should they decide to dual turbo Crank , Rods, Pistons and valve train would be all you need. One of the last Boyd Coddington roadsters had a 1,200 HP big block with two pro chargers and it was a street driven car. My 67 Firebird I built in 72 had 721 HP on the dyno and retimed with street jetting was 668 hp. It was sort of streetable but a big pain to drive with overheating, fan belts flying off and loading up in 5 blocks of slow driving. It amazes me how streetable big HP is now.