You have a post war engine from 1953...
M20s that year started at BM20 101 (in August 1952 as the BSA model year for '53 started then and ran from August 52 to August 53) and yours is 98 engines after that....If that concerns you, to put it right you'll need a set of wartime crankcases, a timing cover and a wartime crankcase breather assembly...Also an iron head if your engine has an alloy one fitted....You can use everything else from the engine...Ian
