I remember the SSF slot car parlor well, as my family had relocated to The Industrial City, and it was within walking distance. The location was Del Paso Drive at Arroyo Drive, the former location of Sun Valley Dairy. I believe it later became a KFC, but I don't go there anymore. For some reason I can't recall the name, but it disappeared in the late 60s, along with nearly all other slot car facilities.
There was another, very brief fling with slot cars in South City about 25-30 years ago. I believe it was in the former Rexall Drugs store at Camaritas Avenue and Hickey Blvd. It lasted just a couple of years, and I never went inside before it poofed. I thought at the time anyone who imagined making a living with that largely dead hobby was a dreamer.