Octane additives?

Back in 1995 I would add a a few gallons of vp c12 to 92 pump gas. Found it is not needed, as I keep the revs up with the manual box in the right gear. Carb, old 1969 440 magnum 750 avs is not jetted for best gas mileage. At the track I throw in some race gas to run 11.6 in street trim with 10.5 slicks