COMP Cams 127650 XFI SPR XE280PH-13 Camshaft Set for 4.6L and 5.4L SOHC Modular 3-Valve Ford for Blower Applications COMP Cams XFI SPR (spring and phaser mods required) XE280PH-13 camshaft set for 4.6L and 5.4L SOHC modular 3-valve ford for blower applications SOHC - race only blower cam with very rough idle, must have ported heads; great mid-range power with incredible gains to 7000+ rpm; requires custom tuning, 4.10+ gears and 3200+ stall Requires valve spring part no 26125-24 Requires steel retainer part no 710-24 or titanium retainer part no 702-24 Requires cam phaser limiter kit part #5449