Just when you’re certain you know a lot about post-war American racing cars, someone steps up to educate you about the depth of your ignorance. Such is the case with the Sabel sports racers, a series of competition cars I knew nothing about until recently. John Sabel grew up in Ross, California, not far from the Golden Gate Bridge. In the early 1950s he and his high school buddies were simply wacky about the automobile. Sabel said, “Many of my…