One correction, Pontiac actually did use the term RAII in 1968. It was used quite boldly in their ad for the 1968 Firebird, with a title "Announcing Pontiac's new RAII..."
Quick rundown of the Ram Air engines, for those non-Pontiac guys...
Ram Air was first offered as an over the counter kit in mid-year 1965 for the tri-power. The kit had the pan, seal, and instructions on how to cut the hood scoop open.
Popularity grew, and Pontiac added Ram Air to the option list in 1966. The kit was delivered in the trunks of GTO's, and had to be installed by the dealer. One of the stranger stories with this setup was that apparently these kits were removed by some inspection workers, thinking that line workers were smuggling parts out of the factory.
In 1967, Pontiac introduced their "Ram Air" engine, which had 4.33 gears out back as standard equipment. Very rare cars. The old high output 400 was dubbed 400 HO.
In 1968, the Ram Air engine continued, as well as the 400 HO. At mid-year, Pontiac released a round exhaust port version of their Ram Air package, and called it Ram Air II. The old 1967 engine was now referred to as Ram Air I.
For 1969, a new engine with redesigned round port heads, aluminum intake, wild cam, and 1.65 rocker arms came out. The original prototype used a funky Ram Air baseplate, and drew air from both hood scoops, as well as air from two large 4" tubes coming off the bottom of the baseplate and running up through the core support. This meant there were 4 ways to get air, and they called it Ram Air 4. Pontiac Engineers decided the air cleaner was too much (although it showed up in a few road tests), and the stylists like the roman numeral designation IV (they said it looked better on the hood scoop), hence Ram Air IV. The Ram Air II was gone.
The old 400 HO was still there, and was marketed as such in the brochures. It was to be the standard 69 Judge and Trans Am engine, and optional on the GTO and Firebird.
In 1970, things remained essentially unchanged. The term "Ram Air" had become so popular, and was so synonomous with Pontiac performance, that the 400 HO was now being called Ram Air III. This actually worked well, as 400 HO didn't signify that it was one step below the Ram Air IV.
All these engines went
pretty well.
A lot of people in 1969 wondered why Pontiac went from RAII to RAIV, but it really wasn't a jump in series, it was a simply a better sounding name than Ram Air III.