Rick,
The 1969 US Nationals were held at Indy, and you can view the results here -
http://www.50th-usnationals.com/apcm...navsource=1969
However, many tracks host "National" as well as "Division" events, a la the "Gator Nationals" in Florida, the "Northwest Nationals" in Seattle, etc.
I couldn't find anything for you on the Gibb-Harrell ZL/1..sorry!
-Sam