That is a nice looking frame (and stem) cocoabeachcrab . I used Rustoleum Gloss Black on this Schwinn Heavy Duti back in the 80"s and it is holding up well. If I were to do it now, I would go with Doug Fattic 's advice and get the 2 component paint. It is much tougher than a single component enamle spray paint. And the spray nozzles that they put on those more expensive spray systems are better than the "made for a low price" rattle can spray nozzles. Eastwood has a 2K "Rat Rod Satin Black". Eastwook 2K Black .

Of course, you know what they say about getting a good paint job. "It ain't the paint, it's the prep".