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This graph illustrates the three power levels from the test we ran in the Oct. ’07 issue. The mechanical roller cam produced slightly better power, but only past 6,200 rpm. We feel this was due more to the mechanical cam’s better valve control because of high spring pressure than any problem with the hydraulic roller lifters. Had we increased the hydraulic roller cam’s spring pressure to better control the valvetrain, the hydraulic roller would have equaled the mechanical cam’s peak power.