This is a MK30 powerhead built to run in the "C" Service Racing class.  Features:  Block has compression stuffers, welded in; Turner 2-ring racing pistons;  Carter carbs, crankcase has been modified for carbs; Open exhaust system; Brass reed cages; FM mag; Small taper crank with racing flywheel; Looks to be .030 bore.  Crankcase has been welded, fine job.  Out of the 8 rings, one is broken.  Very rare piece of racing history.