I learned long ago never to doubt the Internet's capacity to gather (and organize in some valuable way) obscure threads of information. Yet this one surprises me. A site for the car customizer wing of geekdom called Relics and Rods has posted the rear-window plaques from car clubs in scores of American cities, including of course Los Angeles. The page for the San Fernando Valley alone, home for decades to the Van Nuys Boulevard cruising strip, displays more than 100 club plaques — low riders, high riders, hot rodders, other sub-genres — going back generations. On this page, you can see the whole range of SFV club colors and click on each individual plaque.
A few worth calling out on artistic or cultural grounds.
Ritchie Valens played at Igniters parties in the late 1950s.
The Poor Boys were based around Monroe High School when I was there.
The horrible imagery of the Lynchmen evokes the Valley's racist past.
Car clubs weren't street gangs — exactly. But many came close.