If you don't find anybody locally, send it to Fowler Engines in Columbus, OH - they do all my machine work and really know what they're doing. If you go this route, I'd recommend that you buy your pistons first and send the complete lower end with the block. Their crankshaft, rod and balancing work in top-notch.
Also, pickup whatever valvetrain you're using and have the complete valve job done by the same folks. They have all the correct tools for flathead work - unlike a lot of shops that say "Yeah, we can do that". You can always PM me if you need more info . . .