Found today after i finished the cam install on my zz4 that the plugs were wrong. I bought the car with the newly installed zz4 and never thought to check the plugs until now. It had tapered .500 long thread r44t's in it. It should have .750 long threads with gasket plug. I put the rapid fire #5 plugs in it. it picked up nearly 500 rpm's at idle as soon as i started it! I was wondering why the plugs were staying black:o How much power do you think was lost with the wrong plugs if any at all? Thanks p.s... This comp cams part #08-432-8 camshaft really works well:)