Make your own free website on Tripod.com






_________________________

  Engine Building Tips

 
Club News!

 
6 PACK TUNING TIPS,

 
CHARGING SYSTEMS,

 
AMP DRAW CHART,

 
INSTRUMENT PANEL UPGRADE

 
SPARK PLUG READING CHART

 
TIRE SIZE CONVERSION CHART

 
408/416 STROKER BUILD-UPS

  Mopar Small Blocks

  Tech Links Page

  Links page

  Clubs page

 

 

Mopar is a registered trademark of DAIMLER CHRYSLER Corp.

 

 

   
SIX- PACK (6 Barrel Tuning Tips)

I highly recommend the outboard billet plates available from Promax Carbs!
Promax Link


The 440-6 Bbl. setup is the best choice for off-road performance enthusiasts. The 1970-71 carbs are the best choice and the proper jetting is listed in another section. The aluminum Edelbrock manifold is PN-3412046. Some of the 1970-71 cars have been built with a cast iron version of this manifold although all the 1969 440-6 bbl.'s had the aluminum manifold. The other items required are:

Installation Kit - PN-3412099 (Manual; PN-3412100 (Auto.) Air Cleaner - PN-3412058.

When using the standard aluminum Edelbrock 3-2 bbl. manifold on the 440 with Holley carbs with air cleaner and no modifications to the engine, the following re-jetting for maximum off-road performance is required:

Throttle Side Diaphragm Side
Front Carb MMO** .089 drill .089 drill
Center Carbs - Jets #63 #63
Center Carbs - PVCR* .043 drill .052 drill
Rear Carb - MMO .093 drill .086 drill

* Power Valve Channel-Restriction
**Main Metering Orifice (See Figure 9)

NOTE: In all cases the proper size drill is to be used to open up the PVCR, which is located behind the power valve.

For the above Edelbrock manifold system with the manifold heat blocked, with air cleaner and no other changes, the following re-jetting is required:

Throttle Side Diaphragm Side
Front Carb MMO .089 drill .089 drill
Center Carb – Jets #63 #63
Center Carb – PVCR .041 drill .049 drill
Rear Carb MMO .093 drill .093 drill

For the 440 3-2 bbl. system with a cast iron intake manifold with Holley carbs, with air cleaner and no modifications to the engine, the following re-jetting is required:

Throttle Side Diaphragm Side
Front Carb - MMO .093 drill .089 drill
Center Carb - Jets #64 #64
Center Carb - PVCR .052 drill .052 drill
Rear Carb - MMO .093 .089

For the 440-6 bbl. cast iron system with the manifold heat blocked, with air cleaner and no other changes, the following re-jetting is required:

Throttle Side Diaphragm Side
Front Carb - MMO .089 drill .086 drill
Center Carb - Jets #63 #63
Center Carb - PVCR .043 drill .052 drill
Rear Carb - MMO .093 drill .083 drill

Blocking the manifold heat is not recommended because it will result in poor driveability and poor cold weather operation.
The calibrations are not intended for race purposes or with headers or other similar modifications. Also, if the air cleaner is removed, these calibrations will no longer work effectively and require the carb to be reworked. This rework is permanent, requires special tools and should only be done by a carb expert.

To drill out the PVCR, the power valve must be removed. To reassemble, replace power valve and be sure to install the gasket properly.

On some '69 and possibly a few '70 440-6 bbl., the end carbs tend to stick closed. A production change was made which solves this problem and most '70 440-6 bbl. and all 340-6 bbl. should come equipped with these carbs. There are two fixes on these new carbs one for the kill bleed and one for the throttle plate. The kill bleed actuates the end carbs and the change made allows these end carbs to open sooner. Carbs with this change can be identified by a dash one (-l) after the part number of the '69 models. All '70 models have this change. The other change to the throttle plate can be identified in two ways. First, there is a number stamped on the vertical face over the float bowl and if this number is greater than 3149, it has the new throttle plate. By greater than 3149, it is meant newer since that number stands for the date it was made; in this case the 314th day of '69. The other way to identify the new throttle plate is to remove the carb and turn it upside down. The number 199 stamped on the bottom side of the throttle plate means that it is one of the new plates. The number stamped on the older plates is 266.

To determine if the end carbs are stuck, the throttle must be opened manually with the engine shut off. This can be done by gripping the linkage at the center and the end carb so that the throttle of the center carb is fully open and then opening the throttle of the end carb, being sure to keep the center throttle open at the same time. if a loud "pop" or "snap" is heard, then the throttle was stuck and will stick again. The obvious solution to this sticking problem is a set of the new carbs, but the old ones can be fixed. Remove the end carbs and then remove the throttle body. The throttle bore should then be sanded down to the smoothest finish possible. This can be done by starting with 400 paper and then using 600 paper. This is a very difficult procedure and may not result in instant success. Also, as another solution to this problem, the new throttle blades (#199), can be purchased. If this is done and they are installed, the throttle body should be sanded just as a precautionary measure.

RB ENGINE FAMILY
Package - 440-6 Bbl. Super Stocker or Bracket Racer
Carb - Three 2 Bbl. Holley Carbs
Manifold - One-piece Edelbrock Aluminum PN 3412046
Manifold Modifications: Block Manifold Heat
Carb Specifications: Three 2 Bbl. Holley Carbs

Throttle Side Diaphragm Side
Front Carb Main Rest. .089 .089
Center Carb Jet #63 #63
PVCR .043 .052
Rear Carb Main Rest .093 .093

Yellow springs in end carb diaphragms
Kill bleed - .043
Idle Fuel Rest. - .040
Air Cleaner Open with base plate

340-6 Bbl.

The 340-6 bbl. systems differ from the 440-6 bbl. in carburetor distribution so that the carburetors should not be changed from one system to another. The center carburetor on the 340 has 1-1/2 inch throttle plates while th6 front and rear carburetors have 1-3/4 inch throttle plates.

Practically all stock 340-6 bbl. setups run in a lean condition. The car will probably not idle well at times and may stall frequently. Unbolt the front and rear carburetors and locate the two soft lead plugs at the extreme front of the based. Remove the plugs so that a screwdriver may be applied to the previously hidden idle adjustment screws. One eighth of a turn out (counter-clockwise) on these screws should solve this problem.

In order to ascertain whether the carburetors are running rich or lean, place the tip of your finger (this pertains to the end carburetors only) on either of the outermost air idle bleed holes. If the engine "falls off" (decreases in rpm), the fuel mixture is too rich; conversely, if the engine seems to "pickup" and sound stronger, the fuel mixture is too lean.

If you feel that a jetting change is in order, the main jets in the center carburetor can be swapped. The stock #61's can be changed to #63's if a manual transmission is used or #64's if an automatic is employed. These jetting changes should be used only if the vehicle runs through the stock exhaust system with the air cleaner in place. It is an offroad modification and is not meant for competition.

The 340 six pack does not show any appreciable difference being operated with or without intake manifold heat. If at all possible, run the unit like the factory says, with heat. If you must do without, the automatic choke will cease to function properly. In any case, idle screw adjustment is necessary (by removing the soft lead plugs as we have described) but no main jet changes will be needed for either of the end carburetors. While you have the carburetors off the manifold, check for mismatched gaskets that may be impeding full throttle opening. Sometimes they may be installed backwards and partially cover the throttle bore holes in the intake manifold.

The following is the recommended jetting for the 3406 bbl. on the-aluminum Edelbrock manifold.

340-6 bbl. on Aluminum Edelbrock
A "HOT" Manifold with Air Cleaner

Throttle Side Diaphragm Side
Front Carburetor PVCR .086 .073
Center Carburetor Jet #63 #63
PVCR .046 .046
Rear Carburetor PVCR .086 .073

Above must have a nozzle #Rl738 installed in the diaphragm side of both the front and rear carburetors.

A "COLD" Manifold with Air Cleaner

Throttle Side Diaphragm Side
Front Carburetor PVCR .086 .073
Center Carburetor Jet #64 #64
PVCR .046 .046
Rear Carburetor PVCR .086 .073


Nozzle #Rl738 installed in diaphragm side of front and rear carburetors.

Here is an article on how to further tune it although the above is very good. Use these for comparison. There are 7 pages:
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7

BB 6 Pack Linkage Pics

Pics of the BB 6-pac linkage.



Here's pics of a SB 6 pack setup on the dyno. Theres 5 different pics from different angles. There's no kick down linkage, But there's some good reference pics that may help you out.









Click to go back home







 

Copyright 1990-2006 by Northern Colorado Mopar Club.    All Rights Reserved.