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.
Think Mopar might have known something you don't?
