Martin Hill contributed this photo taken at the 1966 "L.A. Times Grand Prix"  CanAm race at Riverside as a "Mystery Car" and your webmaster had no idea what it was or who was driving. 
 
 

Then this thread appeared on the "Atlas Formula 1 Nostalgia Forum" and I clicked on the photo linked from WGD706's posting -- and there was the car!  Ed Hamill's Hamill SR-3 with Chevy power. (Fourth photo down on the right). Hamill finished 12th at the Oct. 30, 1966 Riverside CanAm event.