January 15, 1969 MRJ article, "- Building A Sidewinder GP Chassis -":
April 1, 1969 MRJ article, "- GP Chassis Revisited - ":
Next are some GP car pictures from other races during the MCS/USRA time frame:
January 30, 1969 MRJ GP car pictures, "Mura Pro GP Race Jan. 25":