[JoeC]

SCCA, FIA, ACCUS, USAC, NASCAR, NHRA, all had different rules and it could be a bit confusing to follow them all. Some races were joint efforts that combined rules.
I have some of the racing files from Yenko’s Canonsburg office and one is about 2 inches thick filled with correspondence with FIA and ACCUS. Their rules were slightly different then SCCA. The big tank was needed for long races at Daytona and Sebring, which were international races under FIA. The Camaro big tank may be an option that was just on paper to conform to FIA rules. FIA had a something called “Regulations for Recognition” where you had to submit forms, part numbers, pictures of parts, and pay a fee. You had to “obtain the recognition” in order to race with these parts. It is not clear if they required a minimum amount of parts produced. For comparison, SCCA rules required enough special service parts to be available to all racers.