H Series 4-1 Hood Exit Race Exit Header H22 F20B Honda Acura EG EK DC2 Civic H2BH Series 4 1 Hood Exit Race Exit Header Honda Acura EG EK DC2 CRX Si H Series hood exit race header (4 1 Megaphone) features a true 4 1 Megaphone merge to create equal exhaust flow. A megaphone is added next, to release pressure and increase the speed of the exiting exhaust gases. A small reverse cone is placed at the very end to provide a tiny bit of wanted back pressure. This header delivers the best peak horsepower gains while utilizing a 2 piece