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Holley Tuning Part 1

Installing and adjusting your Holley carburetor:
GM divorced choke style with external float adjustment

To print a copy of this aticle or save a copy for reference please click on this link: Holley Tuning PDF.

After confirming the carburetor mounting surface is clean, place the appropriate carburetor base gasket(s) in place on the manifold, then install the carburetor.

*DO NOT OVERTIGHTEN THE CARBURETOR MOUNTING FASTENERS*

Check your repair manual for the appropriate fastener torque setting. Typical 5/16" carburetor fasteners require 60-80 inch/lbs (approx. 5 to 6.6 ft/lbs). Over-tightening can cause damage to the carburetor throttle body.

Install all peripheral vacuum and fuel lines, and and baseline adjust all choke linkage(s). Again, check your repair manual for appropriate hose and line routing as well as choke settings for your particular make/model of vehicle. Before attempting to start the engine, operate the choke and throttle linkages by hand to ensure t heir proper operation and to check for any potential binding or other interference issues.

*ALWAYS HAVE AN APPROPRIATE FIRE EXTINGUISHER HANDY WHEN FIRST STARTING A NEW CARBURETOR*

Crank the engine for 10 seconds, then return the ignition to the "off" position. Inspect the carburetor and fuel lines for any signs of leaks. Correct if necessary. Operate the throttle linkage by hand checking for a stream of fuel ("pump shot") exiting the pump discharge nozzle just below the choke blade. If necessary, do this 2 or 3 times, allowing a minute or two between crankings if necessary to prevent overheating the starter. Once you have verified a pump shot is present and there are no fuel leaks, start the engine. You may have to feather the throttle for a moment until the engine runs smoothly.

*DO NOT RACE THE ENGINE IF IT TRIES TO STUMBLE OR STALL*

If the engine runs rough or emits black smoke through the exhaust, re-check your choke settings and adjustments and correct as necessary.
To set the fast idle speed: Insert a medium flat blade screwdriver into the slotted tang on the fast idle lever as shown in the white circle in picture #1 below. Twist clockwise to bend the tang down and increase fast idle RPM. Twist counter-clockwise to bend the tang up and lower
fast idle RPM.

Holley Carburetor Fast Idle Settings

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