What's my Dart Worth?
Maybe selling it as a "classic" isn't getting the hits on CL.
If it were me, at that price you're looking for someone that needs a cheap daily driver, that still cares a little about what they are seen in. Your potential audience (if it were me) could be first car for a teenager. There's a lot more steel there than the newer cars. I have my daughter driving my Suburban when she 1st got her license. (yeah, she totaled it, but survived unscathed)
I'd change the description to include "/6 engine, these are known to go over 200K miles" and "very economical on gas, yet still has style", "lots of money invested" or some such.
I'd also include keywords below the description "cheap transportation" "daily driver" etc. to help bring in people who are searching.
Look at the keywords search words at the bottom of some of the "fly by night" used car dealers use in their ads and see if it helps.
You might just be fishing in the wrong pond......
Just my .02