Originally Posted by dddd

Thanks for the comments! The chain is weird, has both long and short links. I don't know what to call it, I've heard of inch-pitch, block-chain and skip-tooth, but don't know how to distinguish them.

Originally Posted by pastorbobnlnh

The chain is a skip tooth and that is the original chainring. IIRC it is known as the Schwinn Hearts ring.

The bike is in such amazing, near original, shape, I'd be hesitant to go hanging modifications on it. But I realize it is yours and you should enjoy it as it best suits you, so I say go for it, or find a buyer who will double your money!