i plan to run summit headers highflow cats and dual flowmaster super 44s all under 300$ from summit . im making an intack as im typing this now , how much more power will i get out from those parts ? and by the way i have a 5.9

 

5 hp maybe a tad more...If you want to make some good HP roller rockers 1.7, push rods(im checking into this) , throttle body ..