What else can be done to increase air flow and thus performance?
You can put on a larger throttle body size along with the addition of an air foil to smooth the flow of the air. 1 5/8″ headers will probably provide one of the largest increases in power. Then there’s also CNC (computer numerical control) porting of the heads which can be done, although that can get quite expensive, it’s quite “THE” air-flow tweak.