I just joined this forum as I just acquired a body for one of these yesterday. I was looking for info on it and this is the only site I found. It was left at a property my boss bought and since I'm a Mopar fan (actually I'm an AMC guy, but I dig pentastars too) he gave it to me. It's the same as the above units, except it's in rougher shape and this one has no front spoiler below the bumper.
My first thought was to build a chassis for it using Jr. Dragster parts and wheels and tires, and build a sort of mini drag-car using something like a 250 Dirtbike engine or maybe something truly twisted like a 750 GSXR motor or something.

Would really be a screamer with my 160-lb. butt in it. Would be a great little unit to promote the shop I work at (I'm an auto tech and we also work on bikes)
But after reading this and seeings as it seems kind of rare, it might be kind of a shame to do something like that with it. Might be better to just sell it to a collector who would be able to use it. What's something like this worth?
There's a dealership plaque on the rear spoiler that says Gotfredsons Chrysler Plymouth, which was a dealership in Lincoln, Nebraska in the 70's and 80's. It's in pretty rough shape, there's some badly-repaired cracks (looks like it got run into something) and there are some cracks around the roof opening where it looks like something got set on it. But if you got the decals reproduced, it would be easy to repair and paint it.
I'd post pictures, but my wife is in las Vegas right now and has the camera. She should be back tomorrow night so I'll post pics tuesday after I get off work.
I do have a bit of a soft spot for Jr. cars, as a kid I blasted around the neighborhood in what I thought was a poorly-proportioned orange Corvette, but I found out many years later that it was a Rupp Monza Jr. And I wish my dad never sold it, it was cherry.
A few years back I acquired a fiberglass T-bucket hot rod body that was somewhere between 1/2 and 2/3 scale (just wide enough to squeeze two skinny adults in) and I was going to build it using a Harley-Davidson Golf Cart rearend (looks like a minature Dana 44) and a four-cylinder motorcycle engine. I got as far as bulding a frame and getting the body and rear axle mocked up and I got short of $ and sold the project.