I got some hedman headers that have 1 1/2 primary pipes and 3" collectors. My exhaust is a dual 3" system. I figured a free flowing exhaust after the headers would make up for the small pipes. I plan to make between 350 and 400 horses. I would really appreciate any help or input from somebody before the mechanic installs them. I just want to know if they will stop me from making my horsepower goals.

 

if you want to make power like that, i would have bought 1 5/8" header personally.

depending on their design, they may flow well enough compared to stock that you can feel a difference, but i think in the long run they may become a weak link.

also, dual 3" is too big. i run dual 2.5" from my long tubes to the bumper on my mustang that is making slightly north of 400 hp.

throw on the headers and do either dual 2.5, or single 3 the whole way back.