Edelbrock 1903 User Manual

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PERFORMER REPLACEMENT SERIES

CARBURETORS FOR Q-JET APPLICATIONS

for non-computer controlled Chevrolet/GMC V8s; 1966-89

CATALOG #1901, #1902, #1903, #1904 & #1906

INSTALLATION INSTRUCTIONS

PLEASE study these instructions carefully before installing your new Carburetor. If you have any questions or problems, do not hesitate to contact our Technical Hotline at: 1-800-416-8628, 7 am - 5 pm, Monday-Friday, Pacific Standard Time or e-mail us at edelbrock.edelbrock.com.

IMPORTANT INFORMATION ABOUT YOUR WARRANTY If you have any problems with installation or performance, do not return to the retailer. The retailer is not authorized to perform

Warranty Service. Instead, call the Edelbrock Carb Tech Hotline at 800-416-8628 from 7am - 5pm PST on weekdays. All returns must

be accompanied by the original purchase receipt. The warranty period is 90 days for new carburetors and 30 days for "as-new" (remanufactured) carburetors.

DESCRIPTION

The Edelbrock Performer Replacement Series Carburetor for Q-Jet applications is a high quality, all new carburetor designed to replace the original equipment Q-Jet spread-bore carburetors found on most 1966 -1989 non-computer controlled Chevrolet/GMC V8s. These carburetors are street legal/stock replacement parts when used on the applications for which they are listed. Edelbrock replacement carbs for Q-Jet applications are compatible with all OEM linkage and components for the years listed, and will fit stock intake manifolds. For best performance, they may be used with the matching Performer or Performer EGR intake manifold for those who wish to use a new stock replacement carburetor.

Five models are available for the following applications:

1. #1901 (750 cfm) - Recommended for most small-block and bigblock Chevrolet/GMC V8s, 327 through 454 c.i.d., in both truck and

passenger car applications using a remote style choke; 1966 to

1973.

2. #1902 (750 cfm) - Recommended for most small-block and big-

block Chevrolet/GMC V8s, 350 through 454 c.i.d., in both truck and passenger car applications using a remote style choke; 1974 to

1978.

#1903 (795 cfm) - Recommended for most small-block

Chevrolet/GMC V8s, 305 through 454 c.i.d., in both truck and passenger car applications using a hot air style choke; 1975 to

1985. (Electric choke conversion, see choke linkage section.)

4. #1904 (795 cfm) - Recommended for most small-block

Chevrolet/GMC V8s, 305 through 350 c.i.d., in truck applications only using a full electric choke; 1980 to 1989.

5. #1906 (795 cfm) - Recommended for big-block Chevrolet/GMC

V8s-454 engines in truck applications only using a full electric choke; 1980 to 1989.

BEFORE YOU BEGIN, ALWAYS REMEMBER TO:

❑ Replace fuel filter. Dirt found in carburetor voids warranty. ❑ Check and replace the air filter if necessary. ❑ Check PCV valve and replace if clogged. ❑ Check all hoses for leaks or cracks and replace if necessary. ❑ Check fuel pump for proper operation and replace if necessary. ❑ Check the intake manifold and cylinder head gaskets for leaks and

replace if necessary.

❑ Check the ignition system: clean and gap or replace spark plugs, plug

wires, and adjust ignition timing.

CARBURETOR REMOVAL

1. Prior to removal make sure that the engine is cool.

2. Disconnect negative battery cable from battery.

3. Remove air cleaner. Be sure to carefully disconnect any hoses from the air cleaner and note their location for re-installation. You may want to mark them with masking tape for easy reference.

4. Disconnect throttle linkage, kickdown linkage (certain automatic transmission applications only), cruise control (if equipped) and any return springs if present. NOTE: Check carefully for the precise location of all these linkages and return springs. You may want to mark them with masking tape for easy reference. Compare throttle arm of your new carburetor with the old one to be sure that all required linkages will hook up. Ball stud is usually removable and must be installed in the proper location (see Figures 1 & 2).

5. Disconnect all wires, tubes and hoses from carburetor and note their location. NOTE: There should be a maximum of one wire to the electric choke and one to the idle compensator solenoid. Any other electrical wiring attached to your carburetor indicates a computer

controlled engine, and Edelbrock Q-Jet carburetors will not function correctly on computer controlled applications. Disconnect the heater tube from the choke housing (#1903 only). If the tube is burned out, replace it. Failure to do so will cause deposits to form inside the carburetor, improper choke operation, and void the warranty.

6. Carefully remove fuel line from carburetor or fuel filter.

TAKE EXTREME CARE NOT TO SPILL ANY EXCESS FUEL. Place a rag

underneath the fuel line to absorb any spillage that may occur . Certain models require two wrenches to remove the fuel line; one to hold the fitting on the carburetor and the second to turn the fitting on the fuel line. Use a tubing wrench to avoid rounding the tube fitting nut.

Figure 1

Throttle arm of #1901

Figure 2

Throttle arm of #1902,#1903,#1904 ݲ

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7. Remove mounting nuts or bolts and or washers. Be sure to put them where they won't fall into the intake manifold upon carburetor removal.

8. Remove carburetor, being careful not to spill any dirt into the intake manifold. Immediately place a clean rag into the manifold to keep foreign objects out.

9. Thoroughly remove old mounting gasket and clean mounting surface. Inspect gasket and match to gasket included with new carburetor.

CARBURETOR PREPARATION

1. Place old and new carburetors side by side and transfer any accessories that are needed onto the new carburetor.

CARBURETOR INSTALLATION

1. Remove rag from intake manifold and install new mounting gasket. NOTE: Do not use any cement, glue or liquid gasket.

2. Carefully place new carburetor on gasket.

3. Replace all mounting bolts, nuts and washers. Hand tighten with a short box end wrench, using even increments alternating between diagonally opposed bolts. Use stock mounting bolts or Edelbrock Q-Jet Bolt Kit #1925. CAUTION: Overtightening may break carb base.

4. For models with externally mounted fuel filters, install new fuel filter, starting threads by hand to avoid crossing or stripping threads. Replace any old or cracked hoses with new hoses designed for use with fuel.

5. Hook up fuel line to fuel filter. Start threads by hand. NOTE: Be sure threads are properly aligned before tightening to avoid crossing or stripping threads. When tightening fuel line use two wrenches; one to hold the fitting on the carburetor and the second to turn the fuel line fitting. Use a tubing wrench to avoid rounding the tube fitting nut.

6. Re-connect throttle linkage, wires, hoses, etc.Your Edelbrock carburetor may have more vacuum outlets than the original. Leave the caps on those outlets which won't be used. NOTE: #1901 and #1902 will accept the stock idle speed compensator bracket, GM #7042682.

7. Re-connect the air cleaner being careful not to over-tighten the mounting nut which could damage the carburetor. Install a new air filter (if needed) and re-connect all hoses. IMPORTANT NOTE: With engine off, make sure that there is no interference when opening and closing the throttle. Be sure that there is no binding or hanging up between idle and wide open throttle as this could cause the throttle to stick, resulting in loss of engine speed control.

8. Re-connect the negative battery cable to the battery.

LEGEND

A - Diverter Port B - Choke Pull-down C - Fuel Inlet D - Exhaust Gas Recirculation (EGR) Port E - Idle Mixture Screws F - Positive Crankcase Ventilation (PCV) Port G - Canister Purge H - Distributor Port I - Idle Speed Screw J - Accessory Port K - Bowl Vent L - Hot Air (#1903 only) M - Fast Idle Screw N - Clean Air (#1903 only) O - 1/4" N.P.T. (Power Brake Port)

O A

E F G E

Front View of #1901 and #1902

Front View of #1903, #1904 and #1906

Typical Rear View

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