None would be overhanging the bore, bore is 4.350". If I use a 4.380" gasket it will have about .060" copper exposed at the spark plug side of the combustion chamber (BBC iron head). If I use a 4.520" gasket it is right at the chamber edge. The difference is .16 CC's, I know it's not a lot but would like to have it. Would the exposed copper be a possible preignition spot?
Thanks
Mark S