Yes, and it’s all the way up top. For the first time in a Big Twin, the valve count is eight total. According to Harley’s chief powertrain engineer, Alex Bozmoski, several needs pushed Harley away from the familiar two-valve, quasi-hemispherical combustion chamber. First is power; a four-valve head has greater power “headroom.” Next is the ability to run such an engine more aggressively lean for emissions without risking damage or giving up power; the more modern combustion chamber along with dual spark plugs per head make this possible. And then there’s packaging: By doubling the number of valves, total valve area can be increased without having to resort to a tall combustion chamber, necessary to accommodate two relatively large valves. (Harley makes the job a little harder by sticking to long-stroke engines, so fitting two huge, free-flowing valves into a comparatively narrow bore forces a lot of compromises.) The resulting combustion chamber in the Milwaukee-Eight is much flatter than the Twin Cam’s, which makes it more efficient, cleaner burning, and less prone to destructive detonation. With a greater detonation margin, Harley can run more aggressive compression ratios—as much as 10.5:1 in the higher-performance versions, almost a full point up on the typical Twin Cam 103.