Fantasy v twin

I bought a few old bike books recently in a bundle and and discovered some cuttings mingled up with everything else. A couple of which were these illustrations of an ohc v twin motor. It's a wonderful looking engine but not familiar at all to me, a bit like the Koehler Escoffier pre-war racing motor but not quite the same. I feel it is a what could have been flight of fancy on the part of the illustrator and what a lovely machine it would have made...