The `67 Chevelle 325 horsepower 396 used a Quadrajet carb and a single snorkle air cleaner, and the 350 horsepower version used a Holley carb with the open element air cleaner.
Odd that they would use a larger carburetor (advertised 750 cfm) on the 325 HP engine than they did the 350HP engine (advertised 585 cfm), then proceed to choke the larger carb with the more restrictive air cleaner and give the smaller carb the better air cleaner.
Silly engineers.
Eric