Allen also designed the cam with a softer acceleration rate to accommodate a more aggressive 1.7:1 rocker-arm ratio. This places the Camshaft Innovation cam at 237 degrees at 0.050 rather than 245 degrees. Given this cam's 0.016-inch lash spec, we subtracted 8 degrees from the 0.050-inch duration numbers. A shortcut to make the comparison between hydraulic and mechanical cams more accurate is to subtract 1/2 degree of duration at 0.050-inch tappet lift for every 0.001 inch of valve lash. The reality is that a mechanical cam includes a clearance ramp designed to use duration to gradually close up the hot lash clearance, which requires several degrees of duration to accomplish. However, it's not accurate to compare a flat-tappet mechanical cam with hydraulic cam specs even at the 0.050-inch tappet-lift numbers. Allen prescribed a more aggressive flat-tappet mechanical grind that appears at first to be a much bigger cam. Canfield owner John Fenton suggested a second cam from Jay Allen, who owns a company called Camshaft Innovations. We also decided to go with a pair of 195cc Canfield aluminum heads. We employed the Competition Products catalog again to choose a Howard's flat-tappet hydraulic cam with a reduced base circle to help connecting-rod clearance.
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