[DanEC]

That's kind of a botched up Holley ad. It advertises vacuum secondaries with dual accelerator pumps but when you click on the video in the ad, it's for a mechanical secondary carb. The ad photo appears to show a loose vacuum can lid just sitting behind the carb - ??? I can't see how dual accelerator pumps could work with vacuum secondaries - vacuum secondary carbs don't have mechanical linkage to open the secondaries, which in turn is necessary to operate the accelerator pump.