you can safely turn up the rpms to 3750 . Kohler command engines are internally balanced to withstand close to 7000 rpms.You will never get an overspeed broken rod in these engines. The plastic gov gear may come apart but not the rod. ... With top speed at 3350, you are near thetop of the torque curve,as soon as you apply any load the engine will start to labor. JD de-tunes engines ,(maybe so the rest of the mower wont wear out so fast...I dont know..).....The only problem that may arise is the engine may surge from too soft of a gov spring , easy enough to replace.