gary55
Well-Known Member
66 cc engine heads left to right. Stock straight plug head = 10.1cc's. Stock slant plug head = 6cc's. Pancake performance head = 7.9cc's. Round finned performance head = 8cc's. Flat fined performance head = 8cc's. While these performance heads are far better made than a stock head, they won't increase compression unless you are replacing a straight plug head. I am not sure how the squish band effects pre ignition if at all. If it has no effect than there should be no worry of early wrist pin or chrome bore lining failures.