Six pack carb mods

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Longgone

Longgone

John/68 Barracuda & Dart
Joined
Jul 12, 2005
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My six pack set-up has a little hiccup at idle. The local Mopar carb guru seems to think that the new base plates with adjustable mixture screws for the outside carbs may get rid of it. I don`t know who they`re made by and/or where to get them. Has anybody done this mod and if so who makes them,where do I find them,and what should I expect to pay for them? Is the mod worth it? Thanks
 
This is a six pack question so I'll ask it here instead of starting another thread. I have a set of the Holley replacement small block six pack carbs that I nought new about 3 months ago. Does the center carb have the power valve blow out protection that Holley has put in the later carbs, or is my carb an "exact replica" of the old carb that needs to have it added?
 
While I have some answers, there's a whole lot more I don't know. I'll hit you with what I have.

The replacement Holley carbs don't have the power valve saver built in. I just installed one in my center carb recently.

The original base plates have idle screws behind the lead plugs in the factory base plate, which is fine for the front carb. But the rear carb is another story. WWW.PROMAX.COM has the billet base plates with the angled idle screws. This plate eliminates the need to pull off the rear carb to make an idle adjustment!

http://promaxcarbs.bizland.com/Sixhome.chtml

I bought one for my set up.
Barracuda456-vi.jpg

Here you can see the factory base plate on the right with the lead plugs removed. This will allow access to the idle screws on the front carb. But adjusting the rear carb is impossible with everything bolted together. The Pro Max base plate is on the left. You can see how the idle screws are splayed outward.




Barracuda455-vi.jpg

Pro Max recommends hogging out the bottom edge of the bowl for better access to the screws. I assembled mine and it looked like I *could* get in there, but decided that it made sense to open it up a bit to prevent re-doing it after assembly.




Barracuda529-vi.jpg

I did the entire up-grade on my set-up. I have the replacement metering plates for the end carbs that take regular Holley jets so it's fully adjustable. I also installed the "performance curve" mettering plate for the center carb aside from the aforementioned rear base plate. I'm yet to fire it up, so I can't comment on my experience with the upgrades. I did do it because of all the positive feedback I got from guys who did the upgrade already and say it works good. It works REAL good. We'll see... =P~



Now, to the problem. If you have a "hiccup" at idle it may be a vacumn leak in a throttle shaft, could be jetted too lean... too rich.... low float...dirt in the bowl... and on & on. Just realize throwing on a $150 base plate might not cure the problem. Get ahold of someone whom speaks Holley fluently. The problem might be else where. What I would do is pop off that rear carb, pull the plugs, and tweak those idle screws an 1/8 of a turn open, and re-assemble. It's tedious work, but you'll get it dialed in if that's the problem. Adjust a bit at a time. If thats not the fix, you now have $150 towards the real repair.

Hope I answered some questions and I wish you luck. The previously provided link for setting it all up is a good start too. They use the Pro Max pieces in the story. The second link is somewhat dated material. That's why they added the ProMax recommendation blurb at the top of the link. Still, it's good info provided. Some people get their six packs running sweet, some people fight with them. Mine gave me trouble in the past so I'm going with a fresh start.
 
While we are on the subject of 6-packs,I have a original nos fuel line set-up for the 6-pack for sale.If anyone is interested in it let me know.
John

Picture 664.jpg
 
I`m aware that the idle mixture screws exist beneath the lead caps, but I was more interested in the rear carb baseplate that has the screws splayed out so they can be accessed without removing the carb. I think I`ll try removing the carb and opening up the screws up a little before buying a new baseplate. The front carb can remain the same. The local Mopar man here was a top tech at the most prestigous carburetor shop for 2 decades before starting his own business. I will start with what info I`ve learned from this thread ,make what changes I can ,and then pass it on to the him ,the expert. From what I`ve read, if you incorporate the metering plate into the center carb it does NOT have a port for vacuum? Thanks guys for all the input.
 
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