But the 70 GTO could also be ordered stripped, with no sound deadener, to the point where it weighed what a GT-37 weighed (minus the Endura nose). The GT-37's were more bare bones to cut costs, and allow a buyer a cheap GTO of sorts (like a Pontiac "Road Runner"), very much like the original E/T (Judge) was supposed to be. The marketing of this car was 1) Cheap performance 2) Cheap insurance
A buyer could order a 70 GTO gutted, and the Ram Air setup would put 70 GTO RAIII ahead of a GT-37 RAIII, assuming of course they made those.
As for the RAIV not keeping with a RAIII? Considering the RAIV round port heads, aluminum intake, and especially the RAIV cam and valvetrain, how on earth would a RAIII outrun a RAIV? So Pontiac made a mistake developing all of these special parts? By that logic, an 70 LS5 Chevelle should beat an 70 LS6 Chevelle, a 73 Trans Am 455 should beat a 73 SD455 Trans Am, a 70 442 should beat a 70 442 W-30, and a 70 GS455 should beat a 70 GS Stage 1.
The RAIII was a great engine, no doubt about that, but the RAIV was better all around. The RAIII was not in the same league as the RAIV, no more than the standard 68 Firebird 400 was in the same league as the 68 Firebird Ram Air II.