There is no such thing as a nice cobra for $20,000. If you are in the LA area .. go to Supercar Sunday in Woodland Hills. They hold this great car show every Sunday from 7:00 am until 11:00 am. Once each month for 7 months or so . .they feature a special marque (Ferrari, Porsche, etc). There are always 6 or so cobras there. A couple are normally Superformance, a backdraft or two, an ERA, and sometimes an original. You will also see other cars "that make noise" and might be better fitted. But check them out. You cannot buy and register a TURNKEY cobra in California .. so you either buy a used one from somebody or you buy a "turnkey minus" and have the drive train installed by a second party. Talk to Backdraft and Superformance ... they will educate you on what THEY can do. Then look for a nice used one that already has a California registration. Expect to pay $40,000 -$50,000 for a good car.
427 Cobra Country--Ford AC Cobra replica manufacturers SUPER-SITE is a good place to check.