Mrytle Motors and Royal Pontiac did the 428 swap on 68 cars and they did have ram air. I have a copy of the September 1968 Popular Hot Rodding magazine with an article about this swap showing a ram air air cleaner.
My comment earlier that '...none of the 428 cars had Ram Air' was in reference to the factory 1967-1969 Grand Prix's, Bonnevilles, etc.
Yes, Royal Pontiac and Myrtle Motors did engine swaps, but they did not restamp engines to have the VIN match the car. Their conversions were simply that, conversions done at the dealer. The same swap could have been made in your garage back in 1968. The appeal and value of an original Royal Pontiac car is the documentation showing that someone back in the day had Royal (or another dealership) change engines under warranty.
Some of the lesser known dealers also did engine swaps to GTO's and Firebirds, many of those dealers we never heard of, because they didn't receive any media attention.
