The 1s car is from SoCal. The "s" was often used back in the 60's and 70's to differentiate between cars running with the CRA and the SDRA. The SDRA (San Diego Racing Association) cars were Modifieds or caged Sprint Cars and raced mostly at Cajon Speedway and the CRA's home track was of course, Ascot. Both groups had cars that would race with the other club on occaision and the "s" was used for scoring purposes. I remember some of the CRA cars using "c" or "LA" too. The CRA was cageless untill 1970 so it wasn't unusual to see bolt on cages.

The paint scheme on the 1s reminds me of the Culbert (CAE) car (or was it Dean Meltzer?) that Jack Clegg drove. My memory is hazy but I think that Dick Fries drove that car too.