Originally Posted by
ecovelo
If so, is it as simple as it looks? Any drawbacks? More importantly... is it sinful to put more modern stem and bars on a vintage bike?

Its easy as putting a quill stem in. Just grease it down and pop that sucker in.
I used one on my Varsity when the bars I wanted to use had too tight a bend to fit through a normal Quill. I needed a stem with a removable faceplate to make it work so the threadless conversion was my best option. Its worked out fine...and I've seen uglier.
Personally I just much prefer the look of a quill to a threadless stem.