Who runs a Six pack setup? Questions about rebuilding and aftermarket parts.

[MykeNytemare]

Hello all,

It's going to be a long winter in New York and I wanted to spend some time rebuilding and modifying the 340 six pack setup I picked up to put on my 383 in the spring.

I want to be somewhat cost conscious, but want to get this done right and only once. I bought the six pack book and have scoured the Internet for info, but would love input from the six pack owners on this board.

My questions are as follows:
1. Are any of the rebuilding/gasket kits E10/E15 resistant? Can't get real gas in lower NY area so I have to account for this.
2. I know the Quick Fuel metering plates are good for being able to tweak the outboards, but would something like the Percy's adjust-a-jet be fine as well. I guess I need to know if there is room to push out the fuel bowls by using an "external" metering plate or if things are too close to risk it.
3. I hear a lot about heat soak/vapor lock/fuel boiling, etc. Would an AN-fitting/braided fuel line setup with some 1/4 Phenolic spacers be a good way to combat this problem?
4. Should I worry about upgrading the accelerator pump assembly and getting one of those newer power valve blowout protection kits and adding it to the center carb?

Some of these questions may be stupid and some more complicated then I could imagine, so I appreciate any input from those who have proper-running 6 packs on their cars.

 

[Sixpaksteve]

Hi Myke,

I'll respond to your 6 Pak post with my 2 cents worth based on my personal experience, and I'm sure that others will too so you'll have a variety of opinions to consider. That one of the things that makes this site so cool.

My 1970 Cuda was born with a 440/6 Pak automatic, and when I bought it 15 years (+,- ) ago I had to finish the restoration the previous owner had started. I'm a "want to get this done right and only once" guy myself, so for me (and I emphasize, FOR ME) this meant finding the correct factory carbs, linkage, etc... and other parts specific to my car and engine. I had the 3 Holley carbs rebuilt locally by a guy who knew those carbs, and when the time came to put them on the car he came to my house and fine tuned them for me. Everything engine-wise is stock under my hood, and I have zero problems with my 6 Pak setup today.

This might not be the least expensive route for you to take, but IMHO staying true to doing it how the factory engineered it will more than likely satisfy your "want to get this done right and only once" goal.

If you don't have a guy local to you who can rebuild Holley carbs correctly, Holley will do it for you (https://www.holley.com/ ) or I'm sure that some members here on FBBO have someone they can recommend.

Good luck with your winter project, I've got one of those going on myself.

 

[AMX364]

I do not have a six pack, but the metering plates must be kept(at least on one outboard carb-bowl clearance). Now I have run a 2x4 400 cfm carters on a 383 for a few years. I would weld in a wide band fitting and monitor the readings. The stock jetting SHOULD be a good starting point, but todays gas is different then what it once was. This is not what you want to hear.

 

[MykeNytemare]

Well, when I had the exhaust dumpers welded into the exhaust, I also had an o2 bung welded in before each one. So once I pick up a FAST or AEM wideband monitor, that part should be easier.

 

[clazar]

I have a 70 RR 440+6. The trouble I have is with the accelerator pump. They leak after 7-8 mths because of the gas we have today. I was told to try a 30cc pump made for alcohol instead of gas. I haven't used one yet, although I plan on changing to it this upcoming spring. I also get some 110 octane gas locally & run it through. Also check to make sure the vacuum pots are working to open the carbs.

Chuck

 

[SlinktRR]

Subscribed, this is in my long term plans as well. Running a 4bbl now. I plan on saving up and buying all new from summit/jegs.

vapor lock I wouldn't worry about it unless you experienced it this past summer with your current setup. If you are concerned, the NOS vapor separator that came stock on the 69-70 6 pack cars is good insurance and would be the factory setup. Spacers may give you problems with hood clearance.

 

[lewtot184]

the accelerator pump diaphragms that are green work with alcohol. a vapor seperator will cure vapor lock. the quick fuel jet plates allow for jet changes and do have changeable idle feed restrictions. your biggest problem isn't none of the above but getting the idle circuts on all three carbs calibrated, no big deal, and changing the jets in the center carb. the idle mixture screws in the end carbs are covered by lead plugs and are easy to pop off. the mixture screws are under the plugs. turn the screws in until lightly seated and then back off 3/4 turn. change the jets in the center carb to 64's and back out the idle mixture screws 1 1/2 turns. this will make for a good start-up baseline. use yellow or purple springs in the vacuum pods on the end carbs and don't modify the vacuum circut or try some kind of mechanical linkage to open the carbs.

 

[Sixpactogo]

I had a six pack that I bought new at the Mopar Nats in 1998. Put it on my 70 Challenger 440 at that time and never had any trouble with it except dealing with the 10-12 mpg.
I never ran any oxygenated or ethanol gas in it. Only 93 premium. I probably put 20K miles on it over the years and sold it to a guy in Australia in 2013. I get emails from him quite often and he hasn't had any issues as far as I know. They have better gas down under than the junk we have so I guess the key is to not run ethanol as it will eat up the accelerator pump in short order. I never had any vapor lock issues but that may be because I had the 3/8 fuel line with seperator and 1/4" return to the tank. Maybe I was just lucky I don't know. Anyway, I hope you know the 340 intake won't fit your 383 and I would consider adding the return line and seperator to you car.

 

[MykeNytemare]

I had a six pack that I bought new at the Mopar Nats in 1998. Put it on my 70 Challenger 440 at that time and never had any trouble with it except dealing with the 10-12 mpg.
I never ran any oxygenated or ethanol gas in it. Only 93 premium. I probably put 20K miles on it over the years and sold it to a guy in Australia in 2013. I get emails from him quite often and he hasn't had any issues as far as I know. They have better gas down under than the junk we have so I guess the key is to not run ethanol as it will eat up the accelerator pump in short order. I never had any vapor lock issues but that may be because I had the 3/8 fuel line with seperator and 1/4" return to the tank. Maybe I was just lucky I don't know. Anyway, I hope you know the 340 intake won't fit your 383 and I would consider adding the return line and seperator to you car.

How much work would it be to add a return line to my car and where is the best place to get the separator?

 

[lewtot184]

any of the fuel/brake line restoration folks like Fine Lines or Right Stuff carry the fuel and return lines. Herb's, Yearone, Classic Industries should have the vapor seperator. or make your own!

 

[MykeNytemare]

any of the fuel/brake line restoration folks like Fine Lines or Right Stuff carry the fuel and return lines. Herb's, Yearone, Classic Industries should have the vapor seperator. or make your own!

I'm actually wondering what I'd have to do to the current fuel system/tank/pump etc to add a return line more than getting the parts.

 

[lewtot184]

I'm actually wondering what I'd have to do to the current fuel system/tank/pump etc to add a return line more than getting the parts.

1/4" tube stub in the pick-up/sending unit. or, buy a new pick-up/sending unit with the 3/8" pick-up and return built in.

 

[uwss]

You can send your six pack carbs to Promax and have them go through it. Next, you can have them dyno the carbs on an engine and get the perfect setup. I add a neutralizer to the ethanol gasoline and do one part race gas to 4 parts 93 octane. ethanol is the worst thing for ur engine.

 

[Sixpactogo]

Go to Ebay and type in "Mopar 3/8 fuel sender". It appears there are senders with the 1/4" return for almost any car you have. Any of the seperators should work for you. I have seen some of the inline filters that have a 1/4" tee on them and have wondered if they would work in place of the seperator. They are way cheaper than the factory seperator. Go to Ebay and type in "mopar fuel seperator" to get a view of them. Then type in "mopar fuel filter". Some of them have the 1/4" tee on them and I would think they would work the same as the vapor seperator. They send the excess gas and vapors back to the tank so should eliminate the vapor lock in my opinion.

 

[SlinktRR]

The problem with buying vapor separators is that some of the repros are junk and don't work right. I inherited one with my car and it didn't work as intended. After asking around, I found out it is a reproduction with a faulty design (just for OE look).

If you look in the FSM for 69-71 cars it shows the inside of the vapor separator. Its more than just a can with three holes. It has chambers that separate the vaporized fuel out and sends it back to the tank while liquid fuel goes to the carbs. Some repops just have a screen in them. You wont know unless you inspect it.

Buyer beware, basically. This is one item where going NOS or OE is worth it.

 

[Sixpactogo]

That's why I am a member here. Learn something new every day

 

[jonnyp85]

i have a set of six pack carbs for sale check them out
http://www.ebay.com/itm/1969-1970-C...Parts_Accessories&hash=item19fa9fd661&vxp=mtr

 

[mentor70]

i bought new mopar repo sixpack cars in the early 90s, ran them for years with no major drama.

the new holley rebuild kits are more friendly to todays crappy gas. after the first acc. pump replacement, i never had leaks again.

Mopar had other vehicles that used the vapor separators, like the 80s vans i think, they work the same as the originals, but they dont look correct, but they have a Mopar logo on them and they work. never had vapor lock drama with any car i had the setup on.

i had floats stick occasionally.

Holleys factory will also restore your cars, you could tell them which engine they are going on and they will change the out board metering plates to address some of the tuning issues you will have going from 340 to 383. but keep in mind every engine is different so you may not be 100% where you want to be when you start tuning.