Impact of backdating

Here are our favorites: The tooth pitch was changed on the pinion & #2 drive gears starting in 200091-99 style shown on left, 2000-Up shown on right A note on pinion gears: Starting in 2000, HD went to a new, finer pitch on the pinion gear and the matching drive gear on the #2 cam.

This change was then made on all the gear connections for 2001.

Note that some cam grinds are only available in one series or the other.

To retrofit 2000-up cams to 1991-1999 motors, update the pinion gear (available below).

We're proud to offer on this page the grinds that we've had the best success with, and that work the best with our head work. The first spec to look at when selecting your cams is the intake close timing.

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When using cams with a lot of overlap, your torque curve will essentially be a map of how the pipe behaves at different rpm's. TDC lift figures are also very important, and closely related to overlap. Contrary to popular misconception, valve to piston clearance has nothing to do with maximum lift, because maximum lift always occurs with the piston well down the bore.A high compression ratio with early intake close timing is a recipe for detonation.Likewise a low compression ratio with late intake close timing will sap power, especially on the bottom end.Many stock ports will "nose over", flow-wise, at lifts well under .500".That means the port is flowing all it can, and opening the valve farther doesn't make it flow more.