Serious street cam, noticeable idle. Solid power gains above 4600 RPM, requires spring upgrade. Works with tuners, recommend custom tuning. Best with 3.90 gears and 3000 stall. 2,100-6,700 RPM Operating Range 253/270 Duration at .050". 115.5 Degree Lobe Separation Angle 0.491"/0.480" Valve Lift XFI 3V - Developed specifically for the Ford Modular 3 Valve engine's lighter intake valves. VSR - Valve Spring Upgrade Required Fits Ford 4.6/5.4L Modular 3 Valve Made in USA