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V-8 Engine Tech

Reinstating six pack

Mopar Big Block Talk

by peasy » Sat May 18, 2019 12:21 pm

I was wondering if any of you fine people can help me source the parts (and what parts are required) I need to reinstate the six pack on my SP (and who to ask to tune it). it’s currently running fine on a thermo quad, but I’d like to get it back to how it should be (not to mention getting some of the horses back!).
Alex

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by RockyUSA » Sat May 18, 2019 2:12 pm

Not sure I can be much help, but.... Do you have the original 6-pack parts?

I would like to see this go, keep us posted!

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by peasy » Sat May 18, 2019 2:46 pm

Unfortunately, none of the six pack parts are there
Alex

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by Steve Payne » Sat May 18, 2019 3:58 pm

Alex there were companies in the USA a few years ago selling everything as a package but not cheap. If my memory serves me correctly it was over $3000 for the kit. The air cleaner alone was about £500

If your thermoquad is working properly you are not suddenly going to find huge amount of extra HP.

There was a reason a lot of SP's lost the six pack's.

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by Chris_R » Sat May 18, 2019 5:40 pm

Alex, get in touch with Duncan Watts (Cannonball on the forum). He may still have some 6-pack stuff, he did have a while back.
In its original form the SP was quoted around 385bhp and 410 lb.ft of torque versus the standard Interceptor of the time at around 280bhp and 375 lb.ft of torques. If you still have the original high compression 9.4:1 engine (versus the 8.2:1 of the Interceptor), as Steve says your power will be somewhat above the standard and so you may not get back as much bhp and torques as you think - going to the Thermoquad might not have cost very many lost horses.
Also, you need to check that you still have the other 6-pack related stuff in the engine and in the gearbox.
Still, an SP without its six-pack setup is sometimes viewed as not really an SP any more although some may disagree with that. But it won't be cheap. There is a 6-pack air cleaner on ebay USA @ $475 and a complete 6-pack set of 2-barrel Holleys (not the correct Jensen ones) also on ebay USA for $1595 (both plus shipping and import taxes).
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by Jorrocks » Sun May 19, 2019 2:36 pm

Alex,

These are the guys you need:

https://www.herbsparts.com/products.asp?cat=712

Or you could go to six pack efi from Bruce:

http://www.fbthrottlebodies.com/products.htm#billetvc (Twelfth item down)

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by Joe Schiavone » Mon May 20, 2019 12:27 am

Contact Art at Six Pack Performance in Albuquerque New Mexico. They should have a web sight. Been in business since the 70’s at the same location. That is all he does and he has helped emensly. Yes I have a Six Pack have had it up to 135. Still pulling with three people. Runs great. Racer Joe. racerjoe7@gmail.com
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by nrb993 » Fri May 24, 2019 8:05 pm

Hi Chris,

You mention " Not Jensen " Please what is the difference between a standard 440 Six Pack and a Jensen 440 Six Pack.

Is the Jensen Six Pack a different setup to normal, or different sizes

Actually what i wonder is ' normal ' when it comes to Six Pack . Were there a few designs or series and did Jensen choose one of these.

Thank you so much

cheers
Neil
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by johnw » Fri May 24, 2019 8:52 pm

The simplest solution would be to contact that fab website, buy that kit they are selling for $3100, get them to put together a complete fuel system, including mechanical fuel pump, the fuel lines from pump to the carb. Stress you want a complete solution that works together for a 440. That looks such a good deal. Almost unbelievable. Got me thinking about that FF I sold with 383 six pack and wicked headers.

Otherwise, there are quite a few decisions you need to make along the way here. For example, the inlet manifold, would an alloy aftermarket "performance" one do, or do you want the original Chrysler part. Do you have alloy heads on the car at the moment? Do you want vacuum operated secondaries or would you prefer manual (mechanically operated) ones? There are several variations and part numbers for what seem to be six packs.

You could start by compiling a list of part numbers for the original setup, manifold, carbs, engine, transmission, and see what you have. At least when you have done that you will have learnt a bit more. Buying all the bits one by one onn ebay would be a nightmare! People would be sending you old junk, the wrong parts, non of it would work together, etc.
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by Chris_R » Fri May 24, 2019 9:24 pm

Neil, "not the correct Jensen ones" only meant that the model numbers of the Holleys on sale was different to the model numbers used on the Jensen 6-pack. The ones I found were model numbers 4790 & 4792 supposedly fitted on the 340cu in engine.
Jensen fitted the model numbers 6404, 6405 & 6406.
What the difference is or might be, I have no idea.
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by Steve Payne » Fri May 24, 2019 9:36 pm

Chris_R wrote:What the difference is or might be, I have no idea.


The originals had idle mixture screws and I believe the new ones are preset probably for emission reasons.

Knowing how many of the originals are distorted and worn out I would avoid any used ones.

That 3000 dollar kit is a good deal but it will be £4000 by the time they are here and fitted.

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by Joe Schiavone » Sat May 25, 2019 6:28 pm

I have a factory six pack for a 440. The center carborator is a 350 cfm with a choke plate and mechanical operated. The outboard carbs are 500 carbs vaccume. My tranny is a stock tranny with factory linkage adjusted slightly. The linkage on the intake is a bit sloppy and needs to be shimmed so all movement is straight back wi no slip sideways. I redrilled mine and put bushings in so the rods that pivot do so with no sideways slip. I mentioned Art at Six Pack Perfirmance. You need to set up a relationship from who you purchase your set up. I prefer the ourginal verses the new stuff but that is a personal preference. You may have to wait a while. My car is tuned according Art and never stumbles and pulls like a herd of horses with the stock exhaust no matter how much you spend someone will spend Cubic Dollars and be faster. I own a 74 Drophead with a very shuttle in appearance but feel had Chrysler had continued making the SixPack it surely would have been offered on the Dropheads. My email isracerjoe7@gmail.com Pm for any ?’s. Joe Schiavone
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by johnw » Sun May 26, 2019 2:28 pm

Joe Schiavone wrote:I own a 74 Drophead with a very shuttle in appearance but feel had Chrysler had continued making the SixPack it surely would have been offered on the Dropheads.

I'm sure it would have been offered Joe, along with the FF (had it been available in LHD). The idea of a small centre 350cfm carb for town running is so elegant and sensible. Really mix the fuel well, fast airflow, and a high compression motor for a lean burn. It is not surprising that SP owners can get great MPG (gas mileage). Such an elegant symmetrical idea, compared to a single quad where the town/low throttle venturies are off centre.
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by Joe Schiavone » Thu Jun 13, 2019 2:26 pm

I have checked with Art at six pack performance and the demand for the original Six Pack Package is in very much demand here in the states. The replacement setup carbs are easier to tune but modifications for linkage plus the air cleaner installation will require modifications also. The original 350 carb is straight forward to adjust the outboard carbs have air bleed screws that are near impossible to access while installed in place for best vaccume. Seems the front carb is possible to adjust for Best vaccume then set the rear to the same number of rotations as front for best vaccume possible. Six pack Performance has a great article for the simple tuning. Seems that here in the states people are in demand for correct dates of production in relation to the car build RacerJoe. There is a new base plate that has relocated the air bleed screws that makes them very accessible but you then run into the original verses non original. I have a totally non original part on my 74 and could do not care what others think because very few people are willing to put there car beside mine and go for a comparison point for point. If you have a real Six Pack bring it back best possible and let time be on your side you have a special car that can not be replaced and will get harder and harder to get the parts. There are people out there who will help you get it there. Best of luck. RacerJoe
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by zacmarshall » Fri Jun 14, 2019 6:50 pm

For someone to tune it speak to Rare Performance Motors in Aldershot.

http://www.rareperformancemotors.com/

After a couple of Jensen specialists messed up the six pack RPM sorted it out for me. This was nearly 20 years ago but they still seem to be going.

For the parts themselves take the missus on a romantic holiday to New England and visit Jim's Auto parts.

https://www.jimsautoparts.com/index.html

I brought back a pair of Edelbrock heads in my luggage. It's worth fitting it in with an East Coast national if you can wait that long.

You could always take a leaf out of Colin Mayes' book and ship the car out there :-)
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