1951 Packard 300, entering test track at proving grounds

Packard Co. file photograph of a 1951 Packard nine-tenths left side view, entering test track, people standing at right side. Photo caption on back from Packard News Service: "More than 150,000 miles of grueling tests, over road conditions comparable to those found in all sections of the country, were registered on the new 1951 Packard cars to prove their strength and stamina, at Packard's 504-acre proving grounds, 20 miles north of Detroit, Mich., the new Patrician 400 whips past on the 2.5 mile concrete track as a test driver explains performance of the 300, its Packard Thunderbolt engine develops 150-horsepower, with ultramatic, optional at extra cost, it steps up to 155-horsepower at 7.8-to-1 compression ratio, highest in the industry for full size engines."