Setting up the
4bbl carburetor linkage
Wire the carburetor linkage fully open.
- Install the cross-shaft onto the engine, keeping
the shaft as parallel to
the firewall as possible and fairly horizontal.
- Install the link from the carb to the cross-shaft,
adjusting the length so
that the cross-shaft bellcrank is angled about 30 degrees
- Adjust the bellcrank on the pedal shaft so that it
is angled back toward
the firewall about 20 degrees when the pedal is bottomed out on the
- Install the link from the pedal to the cross-shaft
so that the pedal is about
1/2" from hitting the floor.
- Remove the wire holding the carburetor linkage and
check whether the pedal
is at a convenient height. If it is too high, change the link
link to a lower hole on the cross-shaft. If it is too low,
engine link to a lower hole on the cross-shaft.
- Install the return springs and check whether
you're still getting full throttle.
- Tighten all bolts and jam nuts, check for
interference, and grease all the
- If you want the "smooth look" shown below, cut
some 5/16" brake line to length
to cover the middle section of the threaded rods.
|While most Holley carburetors are similar, small details can
the linkage is set up.
The engine at right, with a low-rise manifold and 550 cfm carb
uses all the
top holes in the footbox bellcrank and linkage cross-shaft.
Note the dual return springs on both setups: One
from the bottom of the carb
to the manifold, one from the manifold to the cross-shaft bellcrank.
|The layout of this high-rise manifold and 750 cfm carb looks
but the link from the footbox goes to the lower hole in the
bellcrank. The link to the carb is in the top hole of the
giving more throw at the carb.