As for vacuum secondaries, I have never found a need for anything other than vacuum secondaries on the street. If you are considering the street demon it only comes with those.
You may have 'never found a need for anything other than vacuum secondaries on the street', but our favorite manufacturer (Mopar) used mechanical secondaries more than anything else. Only the later Holleys used vacuum. ALL of the Carters (AFBs, AVSs, Thermoquads) used mechanical secondaries. And that was on everything from 273s to Hemis.
Not totally accurate, while it's true the actual throttle butterflies were mechanically actuated, the air door in the top prevented them from actually doing anything until that air valve opened as the engines ability to ingest the extra air and fuel increased creating the same effect as a Holley type of vacuum actuated carb. So TQs, QJs, AFBs and AVSs are really considered to be vacuum secondary carbs as the secondaries only work as the engine demands and not the throttle.
Not totally accurate. The secondary air door has an impact on air flow only IF they are adjusted a certain way. While we all understand the function of the secondary air doors (well, maybe some do and some don't) this is the first time I have heard anyone describe the Carters as vacuum secondary carbs. There are a few AFBs that actually used a vacuum pod to operate the secondaries and there are AFBs without secondary air doors.Twist it any way you want to make an argument, but the secondary throttle plates are opened by direct linkage from the primaries (for the vast majority of Carters) and the air doors are above the boosters on most models so that they are as much an enrichment device as they are an air flow control device. The air doors have an impact on the secondaries' operation, but they do not control them. Primary control rests with the linkage and linkage alone.
Mopar's Carters were not vacuum secondary carbs.
