The original and still best bang for the buck - the PowerCore 4 S/A. This is a race design muffler at a value price. It features our exclusive Hi-Flo square core to evacuate exhaust better and provide maximum core surface area for sound absorption. The Hi-Flo technology is evident in the stainless steel formed endcaps as well. For maximum tunability, the PowerCore 4 for a number of applications has a highly versatile modular rear endcap for optional performance accessories – a 2” or 1-3/4” endcap for smoother power delivery, a quiet core insert for the sound conscientious and a replacement spark arrestor screen. Some applications feature a fixed endcap and do not allow for optional performance accessories or a quiet core insert. For further information please contact our Customer Service Representatives by phone. Performance, versatility and pounds lighter than stock – all for an affordable price, FMF’s PowerCore 4…FEEL THE POWER!