Competition Cams 106460 Xtreme XE-R 274BH-16 Camshaft Set for 4.6L DOHC Modular 4 Valve Ford Supercharged or Nitrous Applications DOHC - XE-R Supercharged and Nitrous: Optimized combination for power and torque with acceptable fuel economy for your daily driver or highway cruiser. Programmer upgrade required. 273/275 Advertised Duration, 238/240 Duration @ .050 inch, .475 inch/.450 inch Lift, 116 Lobe Separation Requires cam gear set part #10246SET Requires part #26123-32 valve springs and either 799-32 steel retainers or 798-32 titanium retainers