PLM Power Driven K-Series Hood Exit Race Header (4-1 Megaphone) Non-LeanPLM Private Label Mfg. Power Driven K Series hood exit race header, features a true 4 1 merge collector with megaphone and reverse cone, to create maximum equal exhaust flow. A megaphone is added after the merge collector, 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