Instead of suggesting cars I am going to suggest buying tips.
Do not ever buy anything in primer unless you are more than certain that there is no filler anywhere.
Be very wary of very shiny new paint jobs or crappy rattle can ones, see my thread for the latter
(http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/build-thread-for-the-72-gmc-finally-thanks-john/59103/page26/)
Rust is a killer on many of these, and don['t let someone tell you that it's just a little rust that can easily be fixed. A friend bought a pretty clean Falcon and found the cowl rusted to crap - essentially unrepairable.
If it's been modified, tread carefully. A 305 small block chevy looks just like a 500 hp 383 small block chevy.
Look for unmolested unmodified cars that have faded paint. Drivability issues are usually tuned out easily enough once you learn how to use a carb and a mechanical advance.
Don't buy any sort of race car and try to use it on the street.
Do look for off brands. Even the most obtuse weirdo muscleish car has more of a following than you need for basic stuff. AMC has a few good ones, Ford has a few oddballs and Dodge has plenty.
Ford makes the best rear ends and transmissions. AMC rear ends are terrible. Chevy rear ends are terrible.
If you're not scared of size, try a Cadillac, Buick, Oldsmobile, Pontiac instead of the typical intermediate size car. Big blocks mean big bucks, in chevy and Ford land, though, so be careful. The BOP 455s were pretty good, though, all of 'em. The Caddy 500 is awesome.
Don't fear the truck. Trucks can be easier to work on and still have similar powertrain options from the muscle car brethren.
I love the Catalina 421 option, but it is really a matter of what you like and what you find.
Hooniverse has a 'obscure muscle car garage' series that can be pretty fun:
http://hooniverse.com/2013/08/16/hooniverse-obscure-muscle-car-garage-the-1968-pontiac-grand-prix/
So, to summarize: If someone is selling a shiny car, they just painted over bondo and paper mache. If someone is selling a primer car, it might be worse than that. If someone is selling a stumbling, misfiring car with super MSD spark plug wires, a 6-AL box, braided flex line over their radiator hoses, and some wiring under the hood that looks a little too new, run away. If someone is telling you their 10 second drag car (which never actually broke the 13s, but could have if...) which can -easily- be street driven, run away. If you climb under and find bent crap and bolts that look wrong, run away.
Let us know what you find. Good luck.