[Michael Everson]

How come my new from Ford (Mike Fortes) timing sprocket (lower) has keys all the way around it? Also they are numbered. I put the key on the one that only read 0. Hope I did this right.

 

[CobraDreaming]

That is so you can degree yor cam to various offsets. Basically, it allows you to alter the torque / RPM curve. Best I remember each key slot will move the band 200 RPMs up or down depending on wich side of zero you go.

I'm sure someoneout there can explain it better than I.

 

[Marc A]

Actually those are for degreeing your cam to match up exactly to your engine events(TDC). Cams for some reason are usually some degrees off and are brought back to "center" by using the proper keyway in the crank sprocket.
Marc A