Edelbrock 7516 RPM Air Gap Manifold Installation Instructions

Overview

Catalog #: 7516

Product: Small Block Chevy RPM Air Gap Manifold

Application: For 262-400 c.i.d. V8 engines with Vortec style cylinder heads.

Contact: Technical Hotline: 1-800-416-8628 (7:00 am - 5:00 pm PST, Mon-Fri) or email: edelbrock@edelbrock.com

Kit Contents

• 3 – 3/8"-18 Pipe Plugs
• 1 – 3/8" Pipe to 5/8" dia. Nipple Fitting
• 1 – 7" Length of 5/8" Black Heater Hose
• 1 – 3/8"-5/8" Hose Clamp

Description

The Edelbrock RPM Air-Gap #7516 intake manifold is designed for 262-400 c.i.d. small-block Chevy engines equipped with Vortec style cylinder heads. It accepts late model water neck, air conditioning, alternator, and H.E.I. ignition systems. Use only recommended electric or manual choke square bore carburetors. This manifold is recommended for street high performance and race vehicles, providing good low RPM response and increasing horsepower and torque up to 6500 RPM.

EGR Systems

This manifold does not accept stock EGR (Exhaust Gas Recirculation) equipment or exhaust-heated chokes. It is not legal for use on any emissions-controlled vehicle where such equipment is required. Check local laws for requirements.

Accessories & Installation Items

Refer to the Edelbrock catalog for specific part recommendations based on your vehicle's year, make, and model. To order a catalog, call (800) FUN-TEAM.

Carburetor Recommendations

Reference Key:

• A – Carburetor works with non-EGR or pre-emission control systems.
• I – Carburetor has no provisions for evaporative canister.
• K – Carburetor requires #8008 or #8024 stud, washer, and nut kit.
• O – Carburetor comes with manual choke; can be converted to electric choke using kit #1478.

Throttle Brackets

Due to the design of Vortec style intake manifolds, throttle brackets must attach to the carburetor or carb flange, not the manifold bolt bosses. Such brackets are available from aftermarket suppliers.

Gaskets

Use only an original equipment intake gasket set GM #12529094 when installing this manifold.

Installation Instructions

1. Use only a GM #12529094 intake gasket set.
2. Thoroughly clean cylinder head intake flanges and engine block end seal surfaces.
3. Install intake gaskets onto cylinder head flanges, aligning dowels. Do not use gasket sealer on intake gaskets; O-rings seal without it.
4. Use RTV silicone sealer for end seals (apply a 1/4" bead across each block end seal surface, overlapping the intake gasket at the corners). Do not use cork or rubber end seals.
5. Install intake manifold bolts with Loctite 242 on threads. Tighten evenly until the O-ring section of the gasket is compressed. Torque all bolts to 11 ft/lbs in the sequence shown in Figure 1.

Special Note: Thermostat Bypass

For 1995 and earlier blocks with a thermostat bypass water passage from block to water pump: If using on a 1996+ Vortec engine without this passage, route a thermostat bypass hose from the manifold's bypass port to the water pump's 5/8" nipple. The kit includes the necessary fittings. If your engine block has the bypass passage, use the supplied 3/8" NPT plug to seal the manifold bypass port.

Prep and Tuning for Power

1. The manifold's equal length runners ensure even air/fuel mixture distribution. Stock carburetor jetting generally requires no changes.
2. Aftermarket ignitions and aggressive advance curves are recommended.
3. Use modified stock heads or Edelbrock aluminum heads for best results. Port match manifold exits to cylinder head intake ports (.020" per side).

Camshaft and Headers

This manifold is compatible with aftermarket camshafts and headers for the 1500-6500 RPM range. The Edelbrock #7102 camshaft is recommended. For optimal performance with factory iron heads, use high-performance adjustable rocker arms, studs, retainers, and Edelbrock Sure-Seat valve springs #5703. Valve Spring kit #5794 is also available. When using Vortec cylinder heads with the #7102 camshaft and #5794 springs, check retainer-to-seal clearance, as valve seal boss modification may be required. A recommended compression ratio is 9.5:1. Header primary tube diameter should be 1-3/4". Aftermarket headers or camshafts may require recalibrating the carburetor with richer jets.

Warranty Card

Please complete and mail your warranty card, noting the product model number.

General Instructions for Manifold Removal and Installation

Carefully study and understand these instructions before removing your stock manifold; failure to do so may void the warranty. Contact Edelbrock direct for any questions. Improper installation can result in low mileage, poor performance, and costly re-installation.

Preliminary Checklist

• Study all instruction sheets.
• Verify correct manifold instruction sheet.
• Inspect manifold for shipping damage.
• Check all threaded holes.
• Ensure internal passages are clean and unobstructed.
• Use correct Edelbrock or OEM gaskets with Edelbrock Gasgacinch #9300 and RTV silicone sealant.
• Use Teflon tape or PST thread sealer on pipe plugs, fittings, and bolt threads.
• Remove dowel pins from end seal surfaces on Ford and Chrysler products.
• Use correct carburetor and adapter; always use a new carburetor base gasket.
• Re-install vacuum lines correctly, replacing bad lines.
• Position manifold and follow torque sequence.
• Set ignition timing correctly.
• Check ignition timing systems (vacuum/mechanical advance).
• Check and adjust automatic transmission shift points.
• Check air/fuel ratio before and after installation.
• Check emission parts function.
• Adjust automatic choke correctly.

Note: Refer to this checklist again after installation to ensure all steps are completed.

Edelbrock Warranty

Edelbrock warrants products against defects in workmanship and materials for one year from purchase date, provided the product is properly installed and used normally. Customers requiring warranty assistance should contact their dealer. Edelbrock's obligation is limited to repair or replacement. Edelbrock is not liable for consequential damages.

Things to Do Before Removing Stock Manifold

Tools and Equipment

• Box and open end wrenches
• Socket set
• Distributor wrench
• Pliers (channel locks and hose clamp)
• Screwdrivers (regular and Phillips)
• Torque wrench
• Hammer
• Gasket scraper or putty knife
• Timing light
• Vacuum gauge
• Rags
• Water bucket

Shopping List

• Gaskets (Edelbrock, OEM, or equivalent)
• Pipe plugs (if needed)
• Edelbrock Gasgacinch (#9300)
• RTV High Temp silicone sealer or O/2 sensor safe
• Masking tape
• Modeling clay or putty
• Chalk
• Paper and pencil
• Radiator coolant
• Vacuum gauge
• Teflon thread tape or PST thread sealer
• Check manifold instruction sheet for specific Edelbrock or OEM parts.

Checking Hood Clearance

Note: Check hood clearance before removing the stock manifold.

1. Use modeling clay or putty to create five 2-3 inch high stools on the air cleaner at the front, rear, each side, and the center stud.
2. Close the hood to the locked position and reopen it.
3. Refer to Figure 2 and record the clearance measurements at points A, B, C, D, and E. These measurements indicate the clearance between the hood and the air cleaner.

Manifold and Carburetor Height

1. Remove the air cleaner.
2. Lay a straightedge across the top of the carburetor from front to back.
3. Measure from the block and manifold end seal surface to the top of the straightedge (Figure 3). Record these measurements as OM1 and OM2 for the old manifold, and C3 for the carburetor height.
4. Place a straightedge on top of the new manifold, including any adapters or gaskets.
5. Measure the distance from the end seal surface to the top of the straightedge (Figure 4). Record these measurements as NM1 and NM2.
6. Add the carburetor measurement (C3) to the new manifold figures (NM1 or NM2) to determine the total height.
7. If the new combination is taller, subtract this amount from the original hood clearance to find the new hood clearance.

Caution: Maintain at least 1/2" clearance between the hood and air cleaner due to engine torque. A low profile air cleaner may be necessary if clearance is insufficient.

Note: For engines without end seal surfaces, select a standard point for measurement.

Air Cleaner

Use stock air cleaners unless changing the carburetor. Ensure any new or replacement air cleaner provides adequate hood clearance and functions the same as the stock unit, meeting emissions requirements.

Automatic Transmission Check

To ensure optimal performance, economy, and emissions, check and record the transmission shift points before and after the manifold change. Refer to the manifold instruction sheet, dealer, or a repair manual for adjustment procedures if necessary.

Checking Emission Levels

It is the consumer's responsibility to ensure all OEM emission equipment remains operational after any engine package change. Edelbrock recommends measuring tailpipe levels before and after installation to maintain legal emission levels. Edelbrock is not responsible for vehicle emissions if devices are not re-connected.

Note: If any emission part cannot be re-installed, contact Edelbrock Corporation.

EGR Systems

If your vehicle is equipped with an EGR system (common on 1972+ vehicles), it is legally required to retain this system with the new Edelbrock manifold.

Exhaust Manifold Heat Riser Valve

1. Check the heat riser valve (usually on the passenger side below the exhaust manifold) for proper operation.
2. The valve must move freely from closed to open by hand.
3. When the engine is warm, the bi-metal spring should keep the valve open. If it does not open fully, excessive exhaust heat can transfer through the intake manifold, causing damage.

Automatic Choke

With a cold engine, open the throttle by hand to close the choke blade. Note the tension holding the blade closed; the preliminary setting should be the same after manifold installation.

Brackets

Bracket parts or modifications may be needed when replacing a 2-bbl carburetor with a 4-bbl carburetor. Consult the manifold instruction sheet for required Edelbrock and OEM part numbers and modification drawings.

Clean Engine

1. Clean the engine to prevent dirt from falling into the lifter valley or intake ports.
2. Use a cleaner like Gunk and a brush to thoroughly clean the manifold and surrounding areas.
3. Rinse with water and blow dry.

Vacuum Lines

Vacuum lines are a common source of engine, carburetor, and ignition malfunctions. Before removing the stock manifold, sketch or tag each vacuum line, noting its connection point on the carburetor, manifold, distributor, transmission, emission sensors, and EGR valve. Differentiate between Manifold Vacuum (No. 1) and Timed Port Vacuum (No. 2). Replace all vacuum lines if they appear fatigued.

Manifold Vacuum Check: With the engine at idle, check for vacuum on each line.

Timed Port Vacuum Check: At approximately 1500 RPM, check for vacuum on lines that did not show vacuum at idle.

Removing the Stock Manifold

1. Disconnect the battery.
2. Organize all parts for easier installation. Warning: Do not remove the manifold if the engine is hot.
3. Drain radiator coolant (check specific engine requirements; some engines do not require draining).
4. Remove the gas cap to relieve pressure. Disconnect the fuel line and plug it. Replace the gas cap.
5. Disconnect all carburetor linkages (throttle, springs, transmission, cruise control, automatic choke).
6. Tag and remove coil wires and sensor wires.
7. Remove previously marked vacuum lines.
8. Remove the radiator hose, thermostat housing, and thermostat (if mounted on manifold).
9. Remove all brackets attached to the manifold.
10. Loosen or remove valve cover bolts; valve cover gaskets may need replacement if broken.

Removing Ignition

Caution: Follow instructions carefully to avoid serious damage.

1. Remove the distributor cap.
2. Note the rotor position and mark the distributor housing in line with the rotor point.
3. Note the distributor vacuum canister position and mark the valve cover or firewall in line with the vacuum outlet.
4. Note the position of the points (or magnetic trigger wheel), whether open or closed, and their distance from the point block to the cam lobe. Refer to Figure 5 for details.
5. Remove the distributor.
6. Do not rotate the engine after removing the distributor.

Installing Your Edelbrock Manifold

Port Surface Cleaning

Figure 6: To prevent gasket pieces from falling into ports, lay rags in the lifter galley and stuff paper or rags into ports. Carefully remove all particles. Wipe surfaces clean with rags and lacquer thinner to remove oil and grease. This step is crucial for proper sealing.

Installing Fittings, Pipe Plugs & Studs

1. Do not over-tighten or cross-thread fittings in the aluminum manifold to avoid thread damage or cracked mounting bosses.
2. Use Teflon tape or PST thread sealer. Install fittings, pipe plugs, and carburetor studs from your stock manifold.

Gasket Surface Preparation

Caution: Always use new, recommended gaskets. Check compatibility with aluminum intake manifolds; Fel-Pro Printoseal gaskets are recommended. Avoid Permatorque gaskets.

1. Ensure gaskets are correct for the head and manifold surfaces. The beaded side should face up. Note any left/right side gasket differences.
2. Coat the head surface and the cylinder head side of the intake gaskets with Edelbrock Gasgacinch #9300 (Figure 7).
3. Allow gaskets and surfaces to become tacky. Carefully place gaskets on the head surface, aligning ports and bolt holes.
4. Apply a small amount of RTV High Temp silicone sealer around water passages on the intake manifold side of the gasket (Figure 8).
5. For end seals, use RTV High Temp silicone sealer instead of end seal gaskets. Apply a 1/4" thick ribbon across each end seal surface, overlapping the intake gasket at the four corners (Figure 9).

Manifold Installation

1. Carefully position the manifold on the engine, centering bolt holes with the head bolt holes. Refer to specific manifold instruction sheets for any special instructions or bolts.
2. Apply RTV silicone or Teflon tape to bolt threads where exposed to water, oil, or vacuum.
3. Start all bolts by hand. Refer to individual manifold instructions for the correct torque sequence.

Carburetor Installation

Caution: Use only recommended carburetors listed on the manifold instruction sheet. A new base gasket is mandatory. For non-OEM carburetors, follow manufacturer instructions and use supplied gaskets.

1. Connect all fuel lines, linkage, and throttle springs.
2. Connect all vacuum lines according to your drawings or tags.

Wiring

Connect all electrical wiring as per drawings or tags.

Thermostat

1. Test the thermostat in boiling water to ensure it opens quickly. Replace if questionable.
2. Install the thermostat with proper orientation. Apply Edelbrock RTV silicone to the manifold surface and water neck surface, and to bolt threads. Position the water neck and tighten bolts.
3. Ensure the radiator drain is closed. Replace coolant.
4. Reconnect the battery.

Install Ignition

1. The manifold must be in place and torqued to specifications.
2. Install the distributor with the rotor pointing to your marked position on the housing, and the vacuum can aligned with your mark on the firewall or valve cover (Figure 10).
3. Ensure the distributor is fully seated and the ignition shaft is engaged with the oil pump drive.
4. Rotate the distributor until the points opening (or magnetic trigger wheel) alignment matches the position before removal.
5. Install the hold-down clamp and tighten it.
6. Final timing setting must be made with a timing light.

Re-timing Engine

If the engine was rotated, it must be re-timed. Remove the #1 spark plug. Ground the coil wire. With two people or a remote starter switch, rotate the engine by bumping the starter while feeling for compression on the #1 plug hole. Continue bumping until the crankshaft pulley timing mark shows approximately 5 degrees before Top Dead Center (TDC). Refer to Figure 10 for correct rotor and ignition positioning.

Automatic Choke

Caution: Improper choke setting can cause poor mileage and performance. Follow instructions carefully.

Stock Electric Choke

1. When installing an OEM electric choke carburetor, reconnect the choke wire as removed. Do not use the coil wire.
2. When replacing with an Edelbrock electric choke carburetor, connect the choke wire to the choke cap terminal marked "+". Ensure the other connector is connected to a good ground (Figure 11).

Converting to Electric Choke

Caution: Electric chokes require at least 12 volts.

1. Turn the ignition key to the 'Run' position. Locate a +12V source (e.g., input side of resistor, fuse panel terminal).
2. Do not use the plus side of the coil, as it only provides 8-9 volts.
3. Follow carburetor manufacturer's instructions.

Setting the Electric Choke

Align the index mark on the choke cap with the adjustment notches on the housing. Final setting depends on climate conditions; the cap indicates directions for richer or leaner settings (Figure 11).

Divorced Chokes

Edelbrock may duplicate stock manifold choke mounting or use a heat pad. Choke linkage determines blade opening. Chevrolet applications may use the stock assembly. Specific GM thermostat and dust cover part numbers are available. Edelbrock choke rods are also available.

Setting Divorced Choke

1. Install the correct thermostat on the manifold.
2. Refer to the manifold instruction sheet for the Edelbrock choke rod part number.
3. Set the choke with the engine cold.
4. Ensure the carburetor and thermostat are securely bolted.
5. Insert the Edelbrock choke rod into the spring eye and clip end into the carburetor linkage (Figure 12).
6. Open the throttle by hand and push on the choke blade. Bend the link to match the pre-load condition of the stock manifold (Figure 12).
7. Remove the link from the carburetor end, slide the cover over the link base, and push until it snaps in place.
8. Replace the clip end in the carburetor linkage and install the furnished clip.
9. Open the throttle by hand and work the choke linkage to ensure it moves freely from closed to open. Adjust rod clearance if binding occurs.

Troubleshooting

Water Leaks

• Failure to use new/proper gaskets and sealant.
• Improper thread sealing on fittings and bolts.
• Questionable hoses or clamps.
• Use of chrome thermostat housing.

Vacuum Leaks

• Failure to replace questionable hoses.
• Incorrect reconnection of vacuum hoses.
• Forgetting to connect a hose.
• Incorrect manifold or carburetor gaskets (avoid Fel-Pro Permatorque).
• Failure to use Edelbrock carburetor spacer plates (if recommended).
• Failure to re-torque manifold.

Fouled Plugs and Oil Leaks

• Failure to re-torque manifold.
• Incorrect manifold gaskets and sealant.
• Faulty or incorrect PCV valve.
• End seal slippage or insufficient RTV sealant.

Automatic Choke Problems

• Failure to follow instructions completely.
• Clogged exhaust crossover passages.

Poor Mileage and/or Performance

• Incorrect manifold or carburetor selection.
• Incorrect distributor curves.
• Incorrect automatic choke setting.
• Failure to adjust automatic transmission shift points.
• Improper vacuum hose installation (leaking).
• Failure to set timing correctly.
• Worn plugs, wires, points, or carburetor.
• Restricted air flow due to dirty air cleaner.

Mileage Tips

1. Compute mileage over 4-5 tanks of gasoline.
2. Use a vacuum gauge and drive to maintain high vacuum.
3. Keep tires inflated to the manufacturer's recommended pressure.
4. Keep the air filter clean and replace when needed.
5. Re-adjust the automatic choke for winter and summer.
6. Use light throttle when accelerating.
7. Keep points and timing at maximum factory settings.
8. Check spark plugs and ignition wires every 10,000 miles.
9. Adjust idle in gear for automatic transmission cars to the manufacturer's specified RPM, aiming for highest idle vacuum.

Reference Symbols & Nomenclature

Edelbrock uses a system of symbols for manifold and carburetor selection. The nomenclature explains what parts are needed and identifies specific carburetor features related to OEM emissions equipment.

• A: Carb works with non-EGR or pre-emission control systems.
• B: Carb works with EGR systems.
• C: Adapter for this Carb supplied with manifold.
• D: No Carb lever for auto. trans. kickdown rod.
• F: Use manifold-to-manifold base gasket matching vehicle year/model, unless base gasket is supplied with Carb.
• H: Carb has provision for evaporative canister.
• I: Carb has no provision for evaporative canister.
• J: Do not use Ford variable venturi OEM 2-bbl. Carb.
• K: Carb requires stud, nut, and washer kit #8008 or #8024.
• L: Carb requires #8003, #8004, or #8022 for Chrysler auto.trans.
• M: Ford EGR adapter needed.
• N: Carb accepts factory cruise control.
• O: Carb has manual choke only.
• P: Carb is NOT a stock replacement part.

Edelbrock Corporation Contact Information

Address: 2700 California Street, Torrance, California 90503

Technical Department Hours: 7:00 am To 5:00 pm PST, Monday through Friday.

Phone: (800) 416-8628 or (310)-782-2900

Fax: (310)-972-2730

Email: Edelbrock@Edelbrock.com