The information I received many years ago is that since Ford did not have a true white paint in 1966, only Wimbledon white, Chevrolet Commercial White was used. When the cars were first introduced in the spring of 64, Ford made a limited number of Indy 500 pace cars that were bright white with blue interiors. When I visited the parts counter at my friendly local Chevrolet dealer and asked for Chevrolet Commercial White, they said "Which one?"; there are apparently 6-8 choices. I suppose you can't go wrong having a skilled painter simply match the white side stripes.