When I bought Project Cheap Camaro—a $2,800 1968 coupe with a halfway attached roof and otherwise great bones—I was pretty sure I’d just scored one of the DIY deals of the year. Why was it so cheap?

After a bunch of welding, grinding, drilling, and fitting, Project Cheap Camaro had started to look like a viable project car. At least from 10 feet or so. The car, which had been a hacked-up stalled ...