Competition Cams 127020 Thumpr NSR MT273LL-9 Camshaft Set for 4.6L & 5.4L SOHC Modular 3 Valve Ford SOHC - Mutha' Thumpr NSR (NO SPRINGS REQUIRED): Very rough idle, biggest cam for stock heads. Great power above 4900 rpm. Compatible with stock valve springs, benefits from converter and gears, requires cam phaser upgrade and custom tuning. 273/306 Advertised Duration, 234/254 Duration @ .050 inch, .450 inch/.450 inch Lift, 109 Lobe Separation Part #26113-24 valve springs available but not required Steel retainer part #710-24 and titanium retainer part #702-24 also available