7000
No way of answering this without knowing what model Chevrolet you're referring to.
A Chevrolet dump truck can be sold to local companies that buy cars for scrap. Alternatively it can be sold online on websites like Autotrader, Gumtree, eBay and Craigslist.
18 tons
empty weight
13000
Adam-12 - 1968 Log 122 Christmas - The Yellow Dump Truck 1-13 was released on: USA: 21 December 1968
Fully loaded
The volume that a dump truck can hold depends on the size of the truck. You could say that there is no 'typical' dump truck. The horsepower, the axle weight, and the size of the box are a few of the features that determine how much the truck can hold and haul.
About 10k lbs.
It depends on the density of the material that is loaded on the truck.
I own one with a 5 yard dump box on it. I weigh in at 11060lbs empty.
Please give a specific model. The dump bodies and hydraulic system will be aftermarket, but you there's no way to tell you anything if we don't know whether you're talking about a 1/2 ton C/K pickup or one of the Class 8 trucks Chevrolet manufactured at the time (Chevrolet exited that market in 1980; GMC followed suit when their heavy truck division was bought out by A.B. Volvo in 1988).