whats a 72 Swinger with 18k miles worth?

I see one thing that is pretty interesting on it, it has a rear mounted antenna.
About four years ago when the market was better than it is now, I sold my 73 Swinger that was White with a Blue intereior, 318 with a 4bbl and rally wheels all the way around for $1000. The car ran and drove great. It had a little rust in the 1/4's. The interior was nice other than a few little tears in the front driver seat. It took me a wile to get a grand for it. Your car is cleaner, but I would agree that it is worth no more than $2000-$2500. $4k is pretty high for a 73. I do believe that if you took it to a good detail shop and spent about $200, the car would look pretty sharp.

As for yours having the vinyl roof, it doesn't really have an effect on the value. If anything, it's a little less desirable. But not enough to worry about. If I were you, I would clean it up and enjoy the hell out of it. Thats how you would get the most out of it. Have fun and drive it.

Here's the one I sold for a grand. Like I said, it had a edelbrock 4bbl, rallys all around, plus more. I had just put new shocks on it. It was a fun little car to drive.