Advice on a strange engine number

[Dick Deegan]

Hi There to everyone;

I am looking at possibly purchasing a 1931 Tudor. The engine number on this vehicle is CA1337C. I am told that it is not the original engine and the number to me would signify and early 1928 engine. Apparently the number has the Ford stars on either side of the number. What has me puzzled it the "C" at the end of the number.

Can anyone enlighten me about this number and the significance of the "C" at the end?

Thanks

Dicki