Looks like a 1965 33 hp but the model # should be 33552 (no 6 on the end). Sorry I can't help with the plug - my manual starts at 1973. <br /><br />Peter (former east Saint John boy!)
River Run,<br /><br /> I can't find the cross-reference for Champion Plugs, but NGK recommends B6S set at .030. Hope this helps! I'm sure any Auto Parts store can Cross-Reference them.<br /><br /> Rick