sportster case, flathead cylinders

-well, i want to build a custom, i want to use a sportster case and flathead cylinders, do any of you have any problems with this or advice?

Sounds like a good idea to me. I do not really know what flathead cylinders would be the right size but you will probably have to
bore the cases anyway to accept the big flathead cylinders.

Find a 52 to 56 K model engine and you are there.

ya, but something different would be cool

Yeah, because there are so many K models running around right now ... You can't hardly swing a Vincent for hitting a K model