So I realized I hadn't wandered around craigslist in a while. So to solve that problem, I promptly went to for sale by owner and started pulling up sub $7000 muscle.
This is the results, feel free to add in everything in your area under 7k by owner pre-1975 in the comments section. Who has the cheapest muscle in the country?!
$4,500 (surprised at my first choice?) 1969 Mercury Montego:
$5,800 1968 Ford Fairlane (not sure about modern interior...but BIG BLOCK)
$6,500 1973 Mach 1 Mustang
$4,500 1969 Dodge Charger (not running, but big block Charger at 4500...)
$5,299 Chevy C10 Pickup (might be coolest on the list)
$5,995 Mercury Cougar XR-7 (390 + manual + hood scoop + convertible= winner)
HAVE FUN GUYS!
Edit: Kinja fucked all my formatting, oh well. enjoy the links and pics. I'm sure you guys can handle matching them up.