Just went out and found the casting numbers, and then checked them on line;
216 inline head casting #: 1950-53 3835517 All 216
216 inline block casting #: 1952-53 3835849 216 Passenger, Truck
Another source fro the block casting #:
52 AKCA. AKCM, BKCA, BKCM, KAA, KAM, KAC, KAP, KBA, KBM, KCA, KCM, KCD, KCQ 3835849
53 ALCC. ALCP, BLCC, BLCP, LAG, LAT, LAJ, LAV, LBA, LBM, LCA, LCM, LCC, LCP, LCD, LCQ, LCH, LCU 3835849
Makes me think it's a 52/53 engine. Where do the prefix letters come into play? Still baffled by the DR140622CAL serial number.
