Classic Trucks – November 2019

(Jacob Rumans) #1

TECH INSTALL FABRICATE UPGRADE



  1. Booster Benefits


For those who know Holley


carburetors, if you have a choice


about which carburetor to buy, the


recommendation is to always go with


a carburetor with dropped instead


of straight leg boosters. The dropped


boosters are used in all of Holley’s


4150 performance carburetors while


the standard carburetors are equipped


✦ These are dropped boosters that have been used on
performance Holleys for decades. The booster in the background
is an original drop leg from an early Holley. Murphy prefers later-
model boosters with the gentler radius at the bend that improves
flow and its inside diameter is slightly larger at 0.1 6 0 inch versus
stock at 0.1 4 0 inch.


✦ This is Murphy’s custom booster install tool that accurately
positions the booster and flares the inlet in the main body flange.

with straight boosters. The dropped leg
version boosters tend to be a bit more
responsive at part throttle and therefore
are a little better than their straight
booster cousins.
But don’t despair if you have a
Holley with straight boosters. Murphy
can easily convert these to the more
advantageous dropped style. This is not
something that can be done on a home

workbench, however, as it requires a
custom booster installation tool. Murphy
has built his own fixture that will
accurately position the booster in the
venturi.


  1. In Living Color
    Some Holley tricks don’t have to
    relate to performance. So much of the


✦ Our original
factory ’ 6 0s Holley
was haggard
looking. Murphy
brought it right
back to life with
a rebuild and a
dip in his acid
etching process
that makes it look
like new. Note this
is an older factory
carb with the vent
linkage on the
primary fuel bowl.

52 classictrucks.com

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