Just some info on the Harbor Freight 212cc Predator engines...There are a couple "versions" on the market. First the originals, then they (China) made some "Hemi" style, (plug in center of valve cover), then pre-June 2013 with their original crank/cam, and now they have gone to a Honda spec. crank. Also if you plan on removing the governor and winding it out, you'll need a billet flywheel and billet crank for safety (engine specific!) and a set of heavier valve springs so they don't "float" at high speed along with .035 jet and free flow air filter and exhaust pipe. When ordering those engine specific parts, just refer to the engine sticker for its build date. A lot of go-kart racing sites have everything you'll need to build a stock 6.5HP/212cc motor (3600rpm) into a 10HP+ little "monster motor". (6000rpm+) for couple hundred bucks.