I just received a used Chevy 5.3L Vortec engine (LM7) out of a 2003 Silverado. Everything on it is stock at the moment and I would like to build it so that it can produce more than the stock 300 HP and keep it naturally aspirated if possible. I was already considering changing the cam, intake , and throttle body but would like to know what others have done with these engines and what's recommended. Thank you.