Quote:

... I'd have to dig 'em up, but IIRC some actual wet flow #s that BG provided when the Gold / Silver Claws came out (predecessors to the Demons) showed that the 1.56" venturi w/ annular boosters flowed no more (maybe less?) than a 1.42" venturi w/ downleg boosters...


OK, found the data I was talking about in that previous post. These are the #s that BG listed for their Gold Claw series in different venturi & booster configurations. All these are w/ 1.75" butterflies, slabbed shafts & CNC venturi inserts:

Venturi -- Booster - 1.5" Hg ==> Model
1.562 --- Annular -- 875 ==> "750"
1.425 --- Downleg -- 980 ==> "825"
1.500 --- Downleg -- 1036 ==> "975"
1.590 --- Annular -- 1017 ==> "950"
1.562 --- Downleg -- 1084 ==> "1025"

The Model designations they used at the time don't make much sense to me. The spec sheet had a footnote saying "Model sizes are based on median flow rates observed on a range of engine sizes and RPMs suited to each carburetor."

Regardless, the point I'm trying to convey is the booster configuration can have a major impact on the effective flow rate of any given venturi size.