:
: According to information in a book, Holley
: Carburetors & Manifolds, that I have. .
: .
:
: The 1920 carb came in flow capacities of 160
: and 235 CFM (flow at 3.0 inches Hg).
: Throttle bores are 1-9/16 and 1-11/16 inch.
:
: The 1945 carb came in one size wilth a
: 1-11/16-inch throttle bore and flows 203 CFM
: at 3.0-inch Hg pressure drop.
:
: (Hg is the chemical symbol for mercury. Most
: vacuum gauges we use here are calibrated to
: read in "Inches of Hg" meaning
: "inches of mercury".)
:
: NOTE - You can NOT directly compare CFM rating
: of 1- and 2-bbl carbs to ratings of 4-bbl
: carbs. 4-bbl carbs are usually rated at 1.5
: inches Hg pressure drop whereas 1- and 2-bbl
: carbs are rated at 3 in. Hg pressure drop.
:
: To relate the two measurements, use the formula
:
: CFM flow at 3 in. Hg / 1.414 = Equivalent flow
: at 1.5 in. Hg
:
: Example: for a 235 CFM 1-bbl carb
:
: 235 / 1.414 = 166 CFM four-barrel equivalent
:
: Hope this helps.
: CF