I've also heard of a trick where you grind the tip of the ground electrode down so it only covers half of the center electrode. Something to do with the ground electrode not shrouding the spark and improving the ignition of the air/fuel mixture. That and indexing you might get 3hp It was in Circle Track or Drag Racing mag but those guys are looking for every scrap of HP they can get.

 

Waste of time!

 

Actually, the most common thing I saw was +1hp -2 torque.

Not on camaro's though