Milwaukee Eight bikes come from The Factory in both 107 and 114 cubic inch engine sizes. With high efficiency four-valve heads, Milwaukee Eight engines show great potential for performance gains especially with new design Andrews Milwaukee Eight series camshafts. Keep in mind, cam timing specs for four valve heads look very different from camshafts designed for two valve applications. Engines with four valve heads have much greater flow efficiency so listed cam timing durations are a lot shorter. Bolt-in cams can be used with stock pushrods, however, for ease of installation we recommend the use of Andrews EZ-Install Chrome-Moly pushrods.