Based on the plastic model kit from 1970 by famed car designer Tom Daniel.
From the model description:
Need a drag strip in a hurry? Here's your baby! This is gotta be the world's fastest road grader. The old diesel engine was ripped out and a big blown rat motor was stuffed into the chopped customized grader body. Four giant dual slicks are independently suspended on the rear axles. With a touch of that vintage look, a pair of antique side lamps are mounted up front for night work, and the big chrome scraper blade is just looking for hills to level.