More flow equals more power. However if you do all that (good mods too) you'll also need to have the heads ported, valves enlarged, and the exhaust modded to support the front half of the engine. Your biggest restriction to flow will always be the curtain area of the valves, be prepared to spend some time to get it right otherwise you end up with more air than the engine can handle (front end) and you actually lose power instead of build it. Same holds true for the exhaust, to much flow equals no backpressure to properly scavenge the cylinders during the overlap period. Lots to consider and calculate to do that stuff right and have it work. Most straight out of the box "bolt ons" really don't quite work unless you do all the stuff the manufacturer did to get their results. Even then, the words "results may vary" is a catch all if you dyno test and lose 20 horse instead of gain it (like no restriction exhaust often does).