Mine was a rebuilt 1800 K, standard except for a few stronger bits, new cams: Cam Shield Miller's Running In Engine Oil Keep it over 2,000 rpm for first 20 minutes Running in for 500 miles: no slogging Service and change to ordinary oil at 500 miles Another 500 miles of running-in, no slogging, with gradual increase in maximum speed Recommended rolling road session after 1,000 milesSeems to have turned out fine. Jonathan