The influence that Los Angeles has had on the INDY 500 is HUGE and vastly under appreciated. From the mid 20's up into the 1960's engines by Harry Miller and his chief engineer Offy dominated the field. Other names (errr LEGENDS) include people like Gilmore, Roger Ward, Troy Ruttman, Parnelli and Aggie to name just a few.
WHERE THEY RACED is a complete study of early Los Angeles racing history and innovation and is now online at VHX. In fact the Deluxe version has an additional 90 minutes of extended interviews and vintage car porn - including 2 cars that raced at INDY in the very early years.