To gauge air/fuel ratios, we bolted on a set of specially prepared dyno headers with lambda sensor bungs in each pipe. The O2 sensors worked with the electronics from Daytona Sensors to give a reading of the mixture from each hole. Our small-block Chevy was fitted with a Holley Strip Dominator single-plane intake manifold and Holley’s hot 750 Ultra HP aluminum-bodied carb. First up was the COMP XR294HR cam as our baseline. This cam is a member of COMP’s Xtreme Energy line of hydraulic roller cams, the standard of the industry for performance hydraulic rollers. As expected, the engine performed flawlessly, pulling solidly to 7,000 rpm to set our baseline numbers of 473 lb-ft of torque at 5,300-5,400 rpm and 527 hp at 6,500-6,600 rpm. The Xtreme Energy cam set a mark that would be hard to beat.
Thanks to the COMP two-piece aluminum timing cover, we had the new 4-Pattern cam stabbed in our small-block Chevy in a matter of minutes. This stick featured more lift with virtually identical duration by virtue of its more modern lobes, plus the unique valve timing strategy of the 4-Pattern. Pulling it to the redline showed an overall increase in power throughout our test range from 3,100 to 7,000 rpm, with a substantial gain in torque production through the low and midrange. Scrutinizing the individual cylinder lambda readings from our Daytona Sensors system, we found the cam did improve the air/fuel distribution, tightening the ratio variance by 0.11 ratio points between the inside and outside cylinders. With more power and more even flow into each hole, our COMP 4-Pattern cam lets each of our eight cylinders work to their potential.