BSA C15 Valve guides

[Mascott]

Does anyone know what is the nominal outside diameter of 1960s BSA C15 Valve guides, I know you can get oversized guides but I am wondering what the nominal size is?

[Bess]

Hi,
     I believe they are 45mm long, 1/2" O/D, 5/16" I/D.

Best wishes...

[Mascott]

Thanks