Here is my 1983 Mercian King of Mercia converted to 650B. Quite a beauty and also rides very nicely.

I’m running 650B x 38 Loup Loup Pass tires on Pacenti wheels.

I have it set up as a randonneur  but use it for around town and longer rides.

I’ll forward pictures of my other Mercian later.

Thanks.

Regards.

David