Quote Originally Posted by SlowNA06 View Post
The REAL answer is to gap the plugs at 0.060, run the car up to ~5,800 rpm and see if it's a problem. If it is, try 0.055. If that's not a problem, try 0.057, etc. People gap lower so they don't have to keep replacing the plugs if there was going to be a problem at a larger gap. Generally, larger gaps would get better gas mileage, but if the gap is too large, it will break-up at higher rpm.
Excellent info - thanks.

I started @ 0.055" with my new plugs.

I used to run Champion Cu cores gapped @ 0.060". I would get misfires or knock @ higher RPM (with this "setup"). I blamed Champion - perhaps it was the gap. The cheapo Pt Bosches (not gapped design) performed flawlessly with the same setup.