headset cups look shelby, as does the chain stays. Seat post clamp area is similar, but looks different at the top, may have had some repairs to this area. I'm kind of leaning toward Shelby
Too bad its a Monark, I have a correct chainguard in pink/black.Its off of a Firestone though. It may say Firestone special cruiser on it. Also have fender set that may be a bit nicer.
Snyder built, same as the Hawthorne Zep (minus the fork lock), Rollfast Fastback Sport, and many others. That is a one year only frame with the collet seatpost ('36?). Rustjunkie is the man to ask.
I have done it a few times. However, it does get old turning the cog to a new hole, fighting dangling spokes. I'm used to it now. Usually I rebuild my hubs and then set 'em aside waiting for something to put it on it on.