I am always amazed at how BSA engine numbers look as if they are smacked in by a bored apprentice. They certainly never had a machine to do the job or even a punch holder to line up the letters and numbers. A lot of them will have one number or letter that has been hit at an angle and imbedded crooked into the casting.
Just looking at my numbers now and starting to measure them cos they don't look correct?????
The Pirate.