[threetwos]

In this months Tech Feature in MoPar Muscle magazine they tune my Challenger's SixPack with Pro-Max conversion parts. This was accomplished last year but thats the magazine editors fault! Enjoy! Oh, btw, the parts eliminated a nasty bog that was prevalent in the old fixed metering block factory set-up. It makes a really big difference in drivability and they way the car goes from cruise to Wide open throttle, idle is much 'cleaner' all around better performance and with an assortment of Holley Jets you can tune the carbs with little effort or dis-assembly. I also used the adjustable angled rear billet baseplate which makes tuning a breeze without removing the rear carb. Pretty trick stuff! :rck:

 

[threetwos]

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[threetwos]

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[threetwos]

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[RAM MAN]

I bought that issue, partially just because of that article

I had no idea that was your car - too cool

I still think about swapping in a 6 pack on my car . . .

 

[threetwos]

Oh and my car is not a T/A, it's an R/T. Eddie :nutkick:

 

[threetwos]

I bought that issue, partially just because of that article

I had no idea that was your car - too cool

I still think about swapping in a 6 pack on my car . . .

I think it's great idea Ram Man. I feel that for a true street engine. Ma MoPar's SixPack or Plymouth called it 6BBL, (either way is too cool), is awfully hard to beat. You have excellent torque production at lower rpm's than a big single plane and big 4-barrel carb. Sure you can make more high rpm horsepower form the SP, but on the street, where I like to play, low end grunt is what it's all about, and it has very very good top end. I have had the car at 100+ and it keeps pulling very very hard! :rck:

 

[mopar fan]

Back when I had my 70 6 pack Cuda I was having fits with it running so damn rich. Come to find out the metering block on the center carb was warped. Got that resolved and it ran like a bear again!

 

[RAM MAN]

I need to visit out at Muscle Motors or pick the minds of some other Motor builders - so I can dial in the right combo of cam/carb/heads

its something I keep thinking about, even though it will probably not happen for a little while yet ..

 

[threetwos]

I'd be happy to give you or anyone for that matter my combo Ram Man. It's built for more torque/endurance than all-out H.P. and it's fun to drive.

 

[RAM MAN]

I appreciate the offer and would be open to any suggestions you may have

I won't hijack your thread about this subject, but would appreciate your's and anyone elses .02 on the matter ...

I have a tendency to research the heck out of stuff before I spend 1 penny ... so while I'm saving my pennies .... ( L O L)

 

[threetwos]

Hijack away Ram Man! I condone it! :rck: Seriously I enjoy discussing any 440 builds! I had the block machined at Hensley Racing back in 1998, way before I knew about Muscle Motors or Best Machine Dave Hughes ectt.. Ray Barton and Hensley where my only choices at that time. Since I was near Hensley's I choose them and they took over for the legendary Herb McCandless old shop. Anyways I had the block, magged,cleaned, decked, ARP Studs, .020 over for .030 total since it was a factory 4.350 .010 over block. The Shaker, engine, transmission and Dana are original to the car so I didnt want to get to radical but wanted the best H.D. Parts I could get without detracting from the cars outward appearnce and street nature of the car as well. A complete Comp Cams K-Kit and their Chrome Moly Roller Rockers where choosen. The cam is a special grind which Matt Hensley and the comp engineers desigend for a stout 440 but with alittle less duration and overlap than the 292/.509 cam and a little more lift. Ross Pistons 10.5-1, Speed Plasma Moly rings, Ray barton Sportsman H-Beam,(Manley rods). Edelbrock RPM Heads.

 

[RAM MAN]

I have this saved in my "Favorites" for some time:

http://www.mopar1.us/6barreltips.html



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.

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

Click to go back home

 

[Brian_RO]

looks like a really neat artical too bad i already got rid of my set up.

threetwos, glad to see you got some ink with your car.

 

[threetwos]

Thanks Brian, That stuff from Pro-Max really works. As you already know, a tuned six pack thats "on" is awful hard to beat on the street. Plenty of low speed grunt to get outta the hole, and plenty of air/fuel for top end power. It really shows how far advanced Chrysler Engineering was in the sixties! :rck: