I have read that a double pumper is not a good choice for a car that will mainly be street driven? Nice thread on the work and results of your dyno pull.
Thanks.
My friends car certainly fits into the vacuum secondary carb category described below but that does not mean it will be optimal. It's a trade off like everything else.
From Holley:
"For high performance engines a carburetor with mechanical secondaries has
an inherent advantage over a carburetor with a "controlled" secondary
system (air valve or vacuum diaphragm). This is possible because a
controlled secondary carburetor, until it reaches wide open throttle, will
not have as great a pressure drop below the throttle plates as would a
mechanical secondary unit. The greater the pressure drop below the
throttle plates the more dense will be the fuel/air charge to the engine
and, hence, the more output."
"As a rule of thumb, vacuum secondary carburetors work best on:
Relatively heavy vehicles
Street gearing
Automatic transmission
Engines built more for low-end torque
Conversely, mechanical secondary carburetors seem to work best on:
Relatively light vehicles
Strip gearing (4.11 or numerically higher)
Manual transmission
Engines built more for top-end horsepower"
