Abstract: Means and method for reconditioning engines of the type having a head mounted cam shaft tower holding a cam shaft where the engine head has been damaged by warpage, the invention comprising a shim means for reconditioning the engine and a method for machining the top and the bottom of the engine head to obtain planar parallel surfaces, selecting the thickness of shims to generally correspond with the total thickness of the metal removed from both surfaces of the head, and installing the shims between the cam shaft towers and the head in order that the cam shaft be located at relatively the same fixed distance from the engine block as that in the engine prior to reconditioning.