On the superFlow dyno at Thomson Automotive, our lsx 427 kicked out an impressive 550 hp and 511 lb-ft of torque (sTP correction). This was with no tuning or external adjustment; the ls7 controller was simply plugged in and the engine was run on its preprogrammed tune. We were thrilled with results, as the performance was achieved with off-the-shelf catalog parts and a by-the-numbers assembly. Our engine was fuel-injected and used drive-by-wire electronics. GMPP has the necessary parts if you'd like to go this route. if you're going carbureted, you can use a regular, old throttle cable.