Memory (sometimes off a year or two) states that about 1961, Pontiac started actually filtering the air to the automatic choke. This was accomplished by drilling a hole (1/4 inch maybe?) into the air intake below the air cleaner and above the choke butterfly. A brass tube was pressed into the hole. A piece of neoprene tubing about 1 inch long (vibration joint) then attached the brass tube in the air horn to a tube that ran down to a plate on top of the intake. Removing the plate would reveal a "U-tube" that was inserted into the cross-over heat passage (V-8). The other end of the U-tube went back through the plate, and was then attached to the choke housing.
For a real picture instead of the word picture above, Google Pontiac internal choke tube
Jerry and I agree to disagree on my following statement; but I personally convert ALL automatic chokes to manual on my personal vehicles. To be fair, my vehicles are not stock, thus the auto choke is not programmed for my engines.
Jon
