Nascar has used cowl induction hooked by a duct/ducts to the firewall at the base of the windshield since at least the mid 60s to take in high pressure cold air. Cutting holes in the lid would defeat the high pressure from the windshield base, causing a ram effect into the carb.
Below is Smokey Yunick's # 13, 66 chevelle, BBC air cleaner assembly:
For the ford lovers a 1964 galaxie Nascar air cleaner assembly:
Nascar has been using this style of air cleaner assembly for at least 60 years.
I don't think that was a factory issue for any Pontiac, but going from memory I think I may have seen one in the 70s, 80s on a medium duty chevy truck with a BBC. Since the medium duty trucks had no drive by noise requirements, or smog provisions having to use exhaust stove heated air to pass emissions during that time period. Someone just cobbled some junkyard parts together, and they ended up on a 70s GP would be my guess...........
