Gurney, Reventlow, Bondurant, and Miles were all racing in San Diego in '56... not on a racetrack, or parking lot, but on the Montgomery municipal airport

found on http://thechicaneblog.com/ and here's the info

Del Mar had shut down in Feb 56 and yet, so many racers loved San Diego (it was far from the crazy LA scene, and across the border from anything goes Tijuana)  a relatively small city that they kept coming back to race here.

San Diego has 5 or 6 muni airports, and I can't imagine they had much going on in the 50's... I go to Montgomery to buy avgas and it's not busy at all.

racing at Del Mar Jan 56

and in the Oct of 55


all from http://thechicaneblog.com/tag/john-mcclure/