Why do some cams cause knock retard?

[phoenix64]

Is it the lift, duration, intake centerline, lobe seperation, or is it just unknown?

[pgriffith]

its valve overlap. Which is a combination of things. Too much valve overlap and pcm will read knock.

[njp98]

Isn't it because the sensor picks up vibrations from the knock and that tells the computer to retard and on a stock car they're pretty sensitive so when a bigger cam comes in the vibration increases above normal and the computer thinks its knocking. Thats what I heard, I could be wrong.