Ford 4.6L/5.4L modular 3-valve engines found in 2005 and newer Mustangs are all the rage. COMP Cams XFI VSR Modular 3V (Valve Springs Required) Camshafts deliver a great power improvement over stock levels. These cams are the next step up from the COMP Cams NSR (No Springs Required) Cams and represent a major upgrade in power production. When compared to the NSR, stock valve spring compatible cam series, the VSR cams offer a substantial power gain in the higher rpm ranges. To achieve this, a high-lift design that requires a COMP Cams Beehive Valve Spring upgrade was created to maximize power within the limits of the OEM unmodified cam phasers. These new VSR camshafts are available for both naturally aspirated and supercharged engines, with two levels available in each series; one designed for maximizing mid-range power and torque, while the other maximizes top end horsepower. The performance secret behind these camshafts is in the extensive dyno testing that allowed them to determine precise cam timing events. Combining these optimized timing events with a high-lift lobe design offers substantial improvements in both power and throttle response. Designed to work flawlessly with the factory VCT, which is programmed to retard the cam timing above 4500 rpm, the new COMP Cams XFI VSR Ford 4.6L/5.4L Modular 3V Cams optimize both mid and high rpm performance.
