NO! The 800 AVS isn't too big, for this reason: Air Valve Secondary. That's what the AVS stands for.

With any air valve carb, what you have is basically the front two barrels plus whatever the engine's demand is from the secondaries. The air door tailors the carb size to the actual engine needs.

This is why those Thermoquads worked so well, and why my Mercedes 170 cubic inch six has a German copy of a Quadrajet sitting on its intake.

Q-jet, Thermoquad, AVS all have air doors. I believe AFBs have them too but they're hidden deeper in the carb and aren't externally adjustable. Holley vacuum secondary carbs do the same thing, but with the vacuum pod opening the secondaries as needed.

R.