A dual patteren cam lets more spent gasses to leave the combustion chamber as it takes on Fresh incoming fuel & air mixture. (Which is known as what is called a Over Lap) (were the intake & exhaust are open at the same time)
Where as a single pattern cam The Valves are close before the next one is opened. A Marine cam IF i remember right is basicly a single pattern cam and has a Longer/wider Power band.BUT I could very well be off on this. as I don't know much about marine cams.
God doesn't like ugly.
