A drive system comprises a shaft in rotational engagement with a crankshaft of an engine, the shaft including a first cam having a first quantity of lobes; and a second cam having a second quantity of lobes greater than the first quantity of lobes; and a selection mechanism to selectively engage a follower to one of the first cam or the second cam. A method comprises rotating a shaft having a first cam and a second cam; monitoring operating parameters of a vehicle; operating a fuel pump of the vehicle at a desired capacity based on the monitoring, including selectively engaging the fuel pump to one of the first cam and the second cam.