eBay and Craigslist finds

The simple way to see if road frame is any good is to look at the dropouts - if they are flat steel with no screw adjusters, like these, then it's CRAP. Good frames have cast dropouts, with a makers name (Campag, Shimano, Colnago etc,) cast into them. Also, mudguard holes do not appear on quality race bikes. There are plenty of exceptions, but those rules will get you started.

Full brake housing guides on the top tube, pressed steel dropouts, cheap lugs and fork crown? All from an era before 653 was even introduced. Ciocc, my arse.