Don Vesco used old ones, Firestone stopped in 1966 to produce tire, which was kept under right condition on a place in Salt Lake City. They showed no problems up to 400 mph - they were originial rated for 450+ mph. Over 400 he lost a piece of rubber with no effect on the handling. Don never found out why this part went off but the tire kept his air pressure and shape.
What information you need, is, if this tires was kept on a right place and what rate they was originally.
And test this tire by increasing the speed slowly.