[KobraKarl]

Keith makes the point I think your question was addressing. You are only running a four barrel carb with vacuum secondaries,until you really start to wind ,then you get only what you need,and stock linkage is progressive allowing only to barrells at a mild acceleration.

The main advantage of the secondaries is improved breathing at higher rpms, and two air filters generally feeding four barrells at mid rpm's.

I run the early 550's with #62 main jets ,yellow spring in the secondaries, but the real cfm in a propely sprung secondary carb is ,whatever is needed !, manual secondary is whole nother deal....


Karl