Oh dear, it's almost embarrassing to confess I have a spreadsheet with nearly 500 BTH magnetos listed... The dating of the magneto will be accurate to the month, but of course the engine/unit could have been assembled a little later.
Do I get a free plug? I'm looking for a BTH TT MAGNETO. There are plenty around, but I need an MC1 (the low centre height version) from 1932. I have collected enough bits to build a nice DIRT TRACK MC1 from 1933 which looks identical, and will do for the interim, but the quest for the correct item continues.
Cheers
Leon