we have a set 3964291 heads on a bbc. what is the difference between close and open heads and how do you tell the difference? which one is the better heads?
Closed Chambers were OK but now it is more difficult to get Pistons to match. The Closed chambers run 104 to 109 CCs. The Opens have more combustion area around the spark plugs and are 116 to 119 CCs. The Open Chamber are more common and have a lot more choices. Wanna sell them?