The COMP Cams XFI SPR Ford 4.6L/5.4L modular 3V (Springs & Phaser Mods Required) camshafts are the best way to achieve the most power and torque increases possible with the popular Ford Modular 3V engine. These designs are the next step up from the COMP Cams VSR (Valve Springs Required) cams. When compared to the VSR cams, the SPR cams offer additional mid-rpm power increases as well as substantial power gains in the higher rpm ranges. In addition to increases in horsepower, you can also expect another 800-1000 rpm of useable engine speed and an awesome sounding idle lope to match. To achieve this extra level of performance, lobe profiles and timing events were specifically designed to work with the factory variable cam timing (VCT) system cam phasers for all 2005 and newer Ford Modular 3V engines. These cam phasers were modified with the required COMP Cams Cam Phaser Limiter kit to restrict their movement to no more than 20 degrees. This simple modification gains additional piston to valve clearance, allowing for much larger cam designs. This results in cams that not only maintain low and mid-range power, but have incredible high rpm performance as well, all while maintaining the benefits of cam phasing. As noted by the COMP Cams engineering staff during extensive dyno testing, these camshafts provided the biggest power and torque improvements of any cam series they've ever tested in the Ford Modular 3V engine.
