[Tom Vaught]

Reading thru his article he says the 5 circuits are:
a) The Idle Circuit
b) The Cruising Circuit
c) The Power Circuit
d) The Acceleration Circuit
e) The Choke Circuit.

Different wording but basically the same as a Holley carburetor. He was and I am speaking in general terms here.

Most today say that the idle circuit is controlled by the throttle position and mixture screws and the off idle performance by the Transfer Slot vs the throttle blade position. Mr Francisco calls the Transfer Slot the Idle Upper Discharge Port. Again just a difference in wording.

Mr Francisco defines the Cruising Circuit as being the point where the Carbs Booster (Nozzle) starts to function and fuel is pulled thru the main jets.

Mr Francisco spends little time on the Power System (except for a mention of metering rods used un some cars to allow more fuel at WOT conditions. He does spend a lot of time talking about Multiple Carb set-up to get the addition fuel required at WOT.
For the Tri-Power Guys apparently he really liked Tri-Power Carb Systems and how they drove on many engines.

Very few Pontiac Guys are playing with the Tri Power Holley Carb systems but but a few of us are out there with those systems.

Mr Francisco does a nice job on the Air Density vs Atmospheric Pressure portion of his article and also does a nice job on the the importance of syncronizing carb linkages on multiple carb set-ups. 4 carb and 6 carbs set-ups were a favorite of Hot Rodders in those days. Sometimes 2G Rochesters but also single bore carbs too.

Tom V.