B31 engine year of manufacture

[mr_tench]

Hi, Can anybody tell me how I can find out the year of manufacture of the engine fitted to my 59 B31. The original alternator engine has been changed to an earlier magdyno type. The engine number is BB31.12049.
Thanks,
Roy

[Ian C]

Looking at the records available, your engine was manufactured for the 1954 season as 1954 engine numbers began with BB31.6001 and 1955 numbers began with BB31.15001. HTH