Edelbrock 262-400 User Manual

RPM AIR-GAP MANIFOLD

CATALOG #7501

MODEL: Chevrolet 262-400 c.i.d.V8, 1957 to 1986 Non-EGR

INSTRUCTIONS

• PLEASE study these instructions, and the General Instructions, carefully before installing your new manifold. If you have any
questions or problems, do not hesitate to call our Technical Hotline at: 1-800-416-8628.

• EGR SYSTEM: This manifold will not accept stock EGR (exhaust gas recirculation) equipment . EGR systems are used on some

1972 and later model vehicles and only in some states. Check local laws for requirements. Not legal in California on pollution­controlled motor vehicles.

• MANIFOLD: The Edelbrock RPM Air-Gap manifold has been designed for 262-400 c.i.d. small-block Chevrolet engines. The
manifold accepts late model water neck, air conditioning, alternator and H.E.I. ignition systems. Use the recommended electric or
manual type choke carburetors only. This manifold is recommended for street high performance and race vehicles only. The RPM
Air-Gap manifold provides good low rpm response for street performance vehicles and increases performance above the 5000 rpm
range. It also provides horsepower and torque increases, when used with any mix of aftermarket equipment available for vehicles oper­ating from 1500-6500 RPM.

• ACCESSORIES & INSTALLATION ITEMS: Major recommendations are listed below. However, due to the variety of years, makes
and models to be covered, please review each part listed in the Installation Items section of the Edelbrock catalog to decide whether
more items are required for your specific vehicle than are mentioned in these instructions.

• POWER PACKAGE:Edelbrock RPM Air-Gap manifolds are part of a total Power Package System that can be completed with the
use of Edelbrock Performer RPM aluminum cylinder heads, dyno-matched Performer RPM camshaft #7102, springs, chain set,
carburetors and related parts specifically designed to give you maximum results. Please refer to our catalog for details.

• CARBURETOR RECOMMENDATIONS: If parts required for installation are unavailable locally, contact Edelbrock directly.

CARBURETOR REFERENCE PARTS REQUIRED FOR INSTALLATION

Performer #1407 (750 cfm) A, I, K, O #8036 Throttle Cable Bracket (1972-79 only) or #8012 Throttle Cable Extension Kit

A-Carburetor will work with non-EGR (Exhaust Gas Recirculation) or pre-emission control system.
I-Carburetor has no provision for evaporative canister.
K-Carburetor requires #8008 or #8024 stud, nut and washer kit. Determine length needed before installation.
O-Carburetor has manual choke only.

If electric choke is required use Edelbrock kit #1478.
Note: Manifold has been tested and proved compatible with Holley 0-4779 (750 cfm).

• BRACKETS

1. Due to the design and leg configuration on the Edelbrock manifold, the throttle and kick-down bracket on some model vehicles
requires modification to fit. If this condition occurs with your installation, you may purchase the Edelbrock mounting bracket #8036,
or modify your bracket as shown in Figure 3.

2. The carburetor location has been moved up by 0.7" and forward by 0.125" from the OEM location for maximum performance. If your
throttle cable bracket fastens to the carburetor pad you won’t have a problem. If your bracket fastens to the back of the manifold use
kit #8012. (To install #8012 properly, depress the throttle pedal fully, open the carburetor to WOT, and then install the #8012 extension
to the carburetor). Failure to do this will prevent your throttle pedal from tripping the transmission sensor at WOT. This affects
transmission kick-down and up-shift points resulting in reduced performance.

• GASKETS AND SEALANT
CAUTION: Do not use high performance or competition type intake gaskets for street application. Due to material deterioration under

street driving conditions, internal leakage of both vacuum and oil may occur.

1. Use only Edelbrock #7201, Fel-Pro #1205, or OE equivalent gasket set when installing Edelbrock manifolds for street applications.

2. Apply Edelbrock Gasgacinch sealant, #9300, to both sides of the manifold as well as head surfaces. This procedure ensures a good
seal.

© 1998 Edelbrock Corp. 12/98

3. Eliminate the end seals. Use automotive grade RTV silicone instead. Apply a bead of sealant approximately 1/4" high across the block
end seal surface, overlapping the intake gasket at the four corners. This method eliminates end seal slippage and deterioration.

4. For ease of installation, we recommend using Edelbrock Manifold Bolt & Washer Kit, #8504.

• MANIFOLD TORQUE—Torque all manifold bolts circled in Figure 1 to 25 ft/lbs. See Figure 1 for proper sequence.

• FIRING ORDER AND CYLINDER NUMBERING—For firing order and cylinder numbering, see Figure 2.

• REAR WATER BOSSES

We've included two 3/8"-NPT threaded holes over the rear water outlets of the heads. By plumbing the coolant from these outlets to the

front water crossover, you can reduce overall engine operating temperature. This has proved helpful in circle track racing applications.
If you don't wish to take advantage of this feature, plug the holes with two 3/8"-NPT pipe plugs included with the manifold.

• FINAL TUNING FOR OPTIMUM PERFORMANCE

NOTE: Local emission laws must be checked for legality of any carburetor or ignition changes.

1. Due to design, the fuel / air mixture and cylinder charging are very efficient with the RPM Air-Gap manifold. Generally speaking, the
stock jetting for the Performer Series carburetor #1407 will not need changing. Specific applications may show an increase in power by
enrichening the secondary jetting .003 from the stock setting (from 0.107" to 0.110").

2. Aftermarket distributor curve kits may be used with RPM Air-Gap manifolds.

3. Use modified or high performance cylinder heads such as our #6071 or #6073, and port-match the manifold to the heads.

4. The compression ratio should be at least 9.5 to 1 to work properly with the #7102 camshaft.

5. Installation of aftermarket headers, camshafts or both with an Edelbrock RPM Air-Gap manifold may lean carburetor calibration.
Should this condition occur, recalibrate with a richer jet.

• CAMSHAFT AND HEADERS

The RPM Air-Gap manifold is compatible with aftermarket camshafts and/or headers. Edelbrock has developed a dyno-matched, street

proven camshaft, the #7102 which is suitable for use with the RPM Air-Gap #7501.This camshaft will require the use of high perfor­mance rocker arms, studs, retainers, and Edelbrock Sure-Seat valve springs #5703. Header primary tube diameter should be 1-3/4".

• PLEASE complete and mail your warranty card. Be sure to write the model number of this product in the “Part #____” space.

THANK YOU

12

10

11 4

9

Figure 1—Intake Manifold Tightening Sequence

1

3 2

5

7

6

8

Figure 2—262-400 c.i.d. Chevrolet

Firing Order— 1-8-4-3-6-5-7-2

Turn Distributor Counter Clockwise to Advance Timing

Figure 3—Remove shaded area to provide clearance for throttle

or kick-down bracket

© 2001 Edelbrock Corporation
Brochure No. 63-0048

Page 1 of 8

Rev 1/02

GENERAL INSTRUCTIONS

FOR INTAKE MANIFOLD

REMOVAL AND INSTALLATION

The following instructions must be carefully studied and understood before you remove your stock

manifold. Failure to follow these instructions may void the warranty.

NOTE: Included with your Edelbrock manifold package is a separate manifold instruction sheet. That instruction sheet lists carburetor

selection, installation parts, modifications (if needed), and all technical specifications. This must be read carefully. If you have any

questions please contact Edelbrock direct . See page #8.

CAUTION: Improper installation will result in:

Low Milea ge Poor Performance Costly Re-Installation

To avoid these problems, you must use the preliminary checklist printed below for your convenience.

PRELIMINARY CHECK LIST:

❑ Carefully study and understand ALL instruction sheets.
❑ Carefully check the manifold instruction sheet to make sure it is the correct one.
❑ Inspect manifold for possible shipping damage (if damaged, contact your dealer immediately).
❑ Check all threaded holes.
❑ Check all internal passages with a light and a wire making sure they 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 all pipe plugs, fittings and bolt threads.
❑ Remove dowel pins from end seal surface on Ford and Chrysler products. Use grip pliers for removal.
❑ Use correct carburetor and adapter if recommended. Always use a new carburetor base gasket.
❑ Re-install vacuum lines correctly and replace all bad lines with the correct size.
❑ Position manifold and follow torque sequence correctly as per instruction sheet.
❑ Set ignition timing to correct specification.
❑ Check carburetor, points, plugs, wires and distributor vacuum and mechanical advance systems to avoid possible

problems in the future.

❑ Check automatic transmission shift points before removal of your stock manifold, and adjust linkage after Edelbrock

manifold installation for same shift points (if needed).

❑ Check air/fuel ratio before and after new manifold installation.
❑ Check emission parts for proper function before removing stock manifold.
❑ Adjust the automatic choke correctly.

NOTE: We recommend that you refer to this checklist again AFTER installation to be sure you have completed all steps.

EDELBROCK W

ARRANTY

It is the constant endeavor of the Edelbrock Corporation to give our customers the highest quality of performance products obtainable. Edelbrock
warrants each new product to be free from defects in both workmanship and materials to a period of one year from date of purchase, provided
that the product is properly installed and subjected to normal use and service and that the product is not modified or altered in any way unless
specified by our instructions. Customers requiring warranty assistance should contact the dealer from whom they purchased the product. In
turn, the dealer will contact Edelbrock, and we will determine the method of satisfying the warranty.
Should Edelbrock determine that the product be returned to the factory, it should be accompanied by proof of purchase and a clear notation of
the exact problem encountered. The product must be returned freight pre-paid. If a thorough inspection of the product by the factory indicates
defects in workmanship or material, our sole obligation shall be to repair or replace the product. This warranty covers only the product itself and
not the cost of installation or removal.

EDELBROCK CORPORATION SHALL NOT BE LIABLE FOR ANY AND ALL CONSEQUENTIAL DAMAGES

OCCASIONED BY THE BREACH OF ANY WRITTEN OR IMPLIED WARRANTY PERTAINING TO THIS SALE, IN

EXCESS OF THE PURCHASE PRICE OF THE PRODUCT SOLD.