Six Pack Carbs?
The cathedral center pivot float bowls will work (of course) on the vacuum secondary end carbs, cause they have metering plates, not metering blocks.
The tripower carbs with accelerator pumps on the end carbs use metering blocks on all three carbs, and don't have room for the cathedral bowls, they need the shorter side hung bowls.
Edit: technically, you would only need the side hung on the rear carb..... but would you run rwo cathedrals with passenger side fuel line, and a side hung rear bowl with a driver side fuel line?