In fact, before NASCAR instituted the gear rule, Cup engines were capable of operating more than
10,000 rpm. A NASCAR Cup Series engine with the maximum bore of 4.185 inches (106.3 millimeters) and stroke of 3.25 inches (82.55 millimeters) at
9,000 rpm has a mean piston speed of 80.44 fps (24.75 m/s).
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