IN 1967, Pontiac had to revise their top model GTO according to a GM mandate that limited engine size to 400 in³ and a single carburetor on everything but their sports cars. In response, Pontiac raised the displacement on the the 389 and the High Output (HO) 400 was born.
The 400 HO used a new exhaust manifolds, the 1966 Tri-power camshaft and a Rochester Quadrajet on a new intake manifold. As a more potent option, Pontiac offered the L67 Ram Air option which included stiffer valve springs and a better camshaft.
As with most Pontiacs, the GTO came with a hueg arrary of options which could be ordered with the 400 HO such as power steering, power brakes, air conditioning and a range of gear ratios. Other more cosmetic options were red fender liners and new 1967 Pontiac Rally I wheels.