Knock with Forged Pistons?

[NHRA Super Gas]

At the dyno today the guys working mentioned that a car rebuilt with forged pistons that didn't originally have them will have very different harmonics. Thus the knock sensor won't behave nearly like it should. I was getting some wierd knock numbers today, that would come/go for no real reason, and could possibly have been rich knock, definitely not lean at 11:1 AF.

Thoughts from the group?

 

[wordy1]

I've got a similiar set-up and was getting the same readings, turns out it was driveline related, as once I got traction the knock went completely away.

Still not convinced that its real knock despite what forum members have told me about a temporary lean condition when the tires break loose, 'cause it doesn't knock at all during a burnout, only in 2nd gear. And it goes completely away if I feather it and keep the tires from spinning, and there is none with DR's.

You have any scantool readings we could see?