A whole lot of engineering went in to this "machine". AMF star sprocket, Murray frame, Rollfast cranks. The rear chain is skiptooth, the front is standard, I'd like to see how the cogs are set up on the 3 speed hub. It may have been a trike hub. They even went as far to mount a nice aftermarket chain guard. And modified the brake arms to reach the matching 24" wheels, which are older than the 60's bike. I'd keep it like it is for a conversation piece.