[asphaltgambler]

Twin plugging an iron motor is a must in my experience. The combustion chamber is.........like...cut-in-half a grapefruit. Valve angles all wrong and said above ports too big for that size engine even though long stroke engines require much more runner volume for the same displacement.

Duel plugging these heads require little extra expense in machining and ignition parts. The gain in Hp/Tq comes with decreased total timing and fuel curve.