This is just my opinion but the 455 was never advertised as a Ram Air because it had standard exhaust manifolds where the 400 Ram Air engines had all the Ram Air components making them the complete Ram Air package engine. I guess you can say that 455s are Ram Air inductions since they did have a special carb and intake but lacked the exhaust.
Agreed. It seems it was a package that included the specific carb mated to the Ram Air induction. Looking at the Wallace Racing website, the Ram Air exhaust manifolds were not part of the package -they were the same as the standard 400CI, non-RA. (However, the 1971 Judge was delivered with the standard 455 HO Ram Air engine which included the aluminum intake & Ram Air exhaust manifolds.) The non-Ram Air 455 engines had a different carb number. Only one HP level is given for either engine - 360HP. What I find interesting is that the same 455 in the Grand Prix was rated at 370HP.
Chevy, Olds, & Buick were all planning on installing engines over 450CI in their A-bodies, so Pontiac had to keep up with the competition. As 1970 was the first year of the 455 and buyers were already familiar with the RA option on the 400CI, my guess would be it was a marketing ploy by Pontiac to get buyers to opt for the 455 as a performance option even though the 360HP was rated at a low 4600 RPM's while the RA III was rated at 366HP @ the 5100RPM's. Perhaps the 455 did indeed make 370HP at 5100 RPM's (which was also the redline on the tach), but it's power rating was kept lower for insurance reasons.
The Jan. 1970 Car & Driver
road test of the 455 GTO stated:
"They could have screwed on the big port heads and plugged in the long duration camshaft from the Ram Air IV; that stuff will all fit. It probably would have made the GTO go like a nickel rocket too, but they knew better than to do that. The business of collecting up the spent GTOs that would have fallen along the wayside after a short, dazzling flash and reloading them(with new engines -my interpretation
) on warranty was out of the question. Consequently, the 455 is a torquey, low revving device that makes very little ruckus and works great with an air conditioner. Pontiac very definitely wants you to keep the revs down so the tach has a 5100 rpm redline and a 3.31-to-one axle ratio is standard (w/4-speed, 3.07 w/auto, with 3.55 by special order and nothing more)."
So this review would also indicate that Pontiac was concerned with warranty engine replacements if they had really gone big on the HP knowing that GTO buyers would have been over revving them and blowing them up. The RA 400's could take higher revving and were built for such.