I made 3/8" thick aluminum spacers that go between the carbs and the aircleaner base.
Without them the front fuel line interfered with the base. That was the standard 70-71 aircleaner.
I'm a little surprised to read that the shaker base clears. Anybody know if the AAR/TA base clears?
I know that an A12 base clears easy.

In theory, there is no difference between theory and practice. In practice, there is.