yeah, if you've got a stockpile of vintage, NOS motors lying around, for $150 or less, i'll take ten. do you have any Hendee Motors?
seriously, i would love to use a vintage motor on my bikes. i've got a 39 Colson, and i'm building a '20's Colson Flyer right now. If original, Vintage motors were available, i wouldn't be on this site, or putting them on bicycles. or at least, i'd be putting them on Indian bicycles or something.
and i would be asking 100 grand for the finished bike.
unless you're talking about a 70's vintage Sears Free Spirit or something. those should have a friction drive Bike Bug or something.