Owners manual

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15. With some air cleaner configurations, it may be necessary to use an air cleaner spacer to provide adequate clearance
between the carburetor and the air cleaner. Holley® offers such a spacer (Holley® P/N 17-13). Depending on the overall
height, obtain the proper length 5/16 x 18 stud and install in the carburetor airhorn. Close the hood slowly to ensure
adequate clearance between the air cleaner stud and the hood.
WARNING: Inadequate clearance between the air cleaner and the throttle lever could result in throttle sticking and
uncontrolled engine speed. Check the clearance between the throttle lever and air cleaner for proper
operation. Check the clearance between the air cleaner and the hood before closing the hood completely.
MAINTENANCE WARNING: Fuel system components, including fuel lines and the carburetor, should be inspected periodically
to ensure no fuel leakage and to ensure the soundness of the hoses. Today’s clean emissions engines provide higher
temperatures in the engine compartment. These high temperatures promote faster aging of non-metallic materials.
Hoses that exhibit surface cracks, when bent to 180°, should be replaced. The presence of liquid fuel demands tightening of
fittings, hose replacement, and retorquing of the fuel system component flange nuts. Periodically check the torque on the fuel
bowl screws to 25-30 in./lbs. to ensure proper fuel metering.
GENERAL: Some very important factors to optimize efficiency and performance include: Correct engine timing, correct spark
plug gap and heat range, ignition components in good working order, and correct operation of exhaust heat valve.
WARNING: On automatic transmission vehicles only, install the transmission kickdown adjustment screw and black
retaining clip, as correctly indicated. Failure to attend to this detail may result in a sticking wide-open
throttle or dangerous uncontrolled engine speed.
IDLE MIXTURE NEEDLES:
Idle mixture needles control the air/fuel mixture at idle. These have been preset at the factory and SHOULD NOT need any
adjustments. However, if you feel that adjustment is necessary, you can use the following procedure to do so. When tuning the
idle mixture, you’re actually tuning for the best manifold vacuum. Idle mixture needles are found on the primary metering block.
If you change one idle mixture needle, you must change the other idle mixture needle by the same amount. Here are the proper
steps for setting the idle mixture needles.
1. Attach the vacuum gauge to a manifold vacuum port on the throttle body (Figure 7).
2. Adjust each idle mixture screw (Figure 9) 1/8 turn at a time, alternating between each screw. Turn them equally, until you
achieve the highest possible vacuum reading without adjusting the curb idle speed screw. Turn screws in to lean the
mixture. Turn them out to richen the mixture.
Figure 8 Figure 9
3. Now that the idle mixture is set, it may be necessary to go back and reset the idle speed using the curb idle speed screw,
as shown in Figures 8.
4. If a vacuum gauge is not available, use a tachometer to obtain the highest RPM.