As can be seen from this view down the throat of the carbs, the bore of the center carb is smaller than the outboards. The center carb, rated at 350 cfm, features a 131/416-inch venturi and 111/42-inch throttle plates. The outboard carbs are rated for 500 cfm with larger 191/416-inch venturi and 131/44-inch throttle plates. Two-barrel carbs are rated at a higher-pressure differential than four barrels, so the cfm flow numbers can't be directly compared. The center carb's bores are about the size found on a 550 cfm four-barrel, while the outboards share dimensions with an 850.