TUNING A SIX PACK

[biomedtechguy]

Complete failure with the drilled end carb plates., missing above 4000 in 2nd & 3rd. Magnifying glass revealed swirl marks from the drill/pin vise.

If you "messed up" that process, I would destroy it. That's another reason why I got the Promax jetable outboard carb plates.
I just got these so I have 4 of each size of jets, plus some others for the center carb:

The Promax center carb metering block is fantastic too. Angled rear carb idle mixture screws were a given, as I too found a "workaround" but that was so cheesy and inaccurate...
Unless I have around $5K fall in my lap around the time I'm scraping together every dollar I can to finish my stroker build, I'm going to have to start out with my Promax modded Holley carbs on this Weiand intake, so maximum flexibility and ease of tuning is going to be critically important.

Even now, with the 292°/.509 cam, headers, etc and using my Innovate Motorsports dual wideband O2 system I have benefited from the Promax mods.
Now if I happen to have the coin, I'll have what I consider the ULTIMATE 3x2 induction system, from F&B:

 

[66Satellite47]

Ya, sure wish the Pro Max stuff was available in 1974-75. I later learned that the key to re-sizing the end carb metering plates was to use a reamer, not a drill bit or maybe at least inspect with the magnifying glass to smooth out the swirls. That idle mixture screw & idle opening screw trick really improved my launch as the secondary's opened.

 

[62MAX]

Ya, sure wish the Pro Max stuff was available in 1974-75. I later learned that the key to re-sizing the end carb metering plates was to use a reamer, not a drill bit or maybe at least inspect with the magnifying glass to smooth out the swirls. That idle mixture screw & idle opening screw trick really improved my launch as the secondary's opened.

You may debate me on this but the only thing Promax did that "I" though was an accomplishment that Holley should have done was the end base with angled screws,in over 40 yrs of playing with sixpacks,never found anything I couldn't make/do myself.Something else to think about,why the Holley's on the GM tri-power had no mixture screws in the end carb bases. Get a pair of GM bases and try them,you may be surprised.Also,you can actually modify the O.E.M. secondary metering plate to accept a jet,did that long before Promax or Q/F offered the jetable plate.

 

[66Satellite47]

Interesting, Seemed easier for me to just pull plugs on the stock Mopar idle screws & turn them a bit, only took 1 try to get results I wanted. One or two tries on the idle opening screws. Never considered Chev base plates. We did think about trying to mod the jet plates for screw in jets, didn't seem like enough meat there & clearance in the passage. Might be wrong there.

 

[Bill Monk]

I knooow, you didnt TYPE all of that.
My father bought this big Orange "Coke Bottle Looking" car, in like 1969 May..... My mother fvcking Hated it. Because IT got more love than her. Good! Well? November 1969 I rode home from Los Angeles General Hospital in the freakin back seat of it. "IT" iss an "A12 Super Bee". The ol man, who Iost just 6 months ago at 76 years old used to beat my *** as a kid. This was GOOD! Or I'd surely have ended up in San Quentin or Folsom (Prison)... Now I'm 50 freakin years old, and that MONSTER that was NEVER parked outside all of its' 51 years of existing? Is MINE.
(Rather have my mean-*** Veit Nam Vet Father back) but? Thats life...
And now? After ownin Challengers, Cudas a Coronet R/T Convertible, (that was never finished) WS27L9G103556if youre out there? Y2 Yellow, black top H6W interior, 727 Auto C16 car.. AND now I am fighting this "Six Pack Nightmare"...
Build sheet was lost in a house fire in 1982, first thing OUT of that house? I can STILL remember hearing it start 38 years later...This thing starting saved my Brother and Mother's lives.. (True story!)
View attachment 981652 View attachment 981653 View attachment 981655 View attachment 981656

Outstanding! great looking car man

 

[RM23M9A]

Well! I'll remember that!

Christ, I used to cuss and throw Sh"t about 4 barrels at one time...LOL
Oh boy, well? I inherited what I never DARED to "Go Near" or could only SHOW my teenaged friends in the 1980's... When I had to sell his house, help my Asshole brother take care of his "Final Wishes" etc, I finally got it into MY garage after finally getting out of the Army in 2008. I knew one day I'd own it. Hating or just disliking a man's Father goes away pretty fast when the inevitable happens..
When I first began to actually take it out & drive this "A12" it ran FANTASTIC. It's a ROCKET, when it runs as it should. Anyway, 3 weeks ago, I ran into long time friend who owns a 68 SS 396 Camaro, (hehe), well? Yeah we know what happens, at even 50 yrs old I was not letting a P.O.S. Bowtie pass this car I've NEVER seen passed by another '60s/'70s Big Block car.. Was always the ol man driving and I usually scared shitless... 10 yrs old? 140 mph? NO SEATBELT.. What the hell was a seatbelt? We all learn that eventually.
After 7-10 short drag races vs this weak-*** 396 (He never has passed this 440 Six Pack since Ive had it).
It falls FLAT ON ITS FACE, when literally "Putting Around", carbs are 51 years old. Todays gas is crap. I've replaced:
DASH WIRING-ENGINE WIRING (Year One), ECU-COIL- BALLAST RESISTOR-WIRES-CAP-ROTOR-Volage Regulator, rebuilt the damn guage cluster! **** works now that hasnt in 35+ years. (Except fuel Guage)... (There IS this, it seems to work) "Hi Rev7500"?

If I stomp into it, past the cruising RPM? It's a Bat Out Of Hell again..In between? Runs like a 300,000 mile Honda Accord with an automatic.

My thoughts are to just BUY ALL NEW Carburetors. A/F screws are stripped on #1 outboard, Ive rebuilt Thermoquads, QuadraJunks, Holley 750s, but this is my FIRST "Six Pack" car. Pain in the ***. I'm not rebuilding just one, and then have to REMOVE it, to service the other 2 within a few days. This my luck. Lets call it "History". Should have STAYED in the damnned Army.

Advice? IF I can afford to buy at least the Center 4144 and ONE Outboard carb? (For right NOW) Anyway. Im sick of "Throwing Parts" at it. Not looking to sell it...(Yet) but getting there.
[Sorry for long *** post, but with other guys quitting L&R,17 hr shifts are murder]... Yeah I just typed that..lol

 

[RM23M9A]

Outstanding! great looking car man

Thanks!

 

[GrabberOrange69]

...We did think about trying to mod the jet plates for screw in jets, didn't seem like enough meat there & clearance in the passage. Might be wrong there.

Actually, someone makes, or used to make what you describe. Haven’t thought about one in a while as I have eddy/AFB carbs.

 

[RM23M9A]

Some interesting thoughts on this one... hmm, I can only get mine to run 10's in street trim..? Gotta be doing something wrong..

View attachment 510085

TimeSlips?

 

[RM23M9A]

View attachment 435752 Any Suggestions for THESE DIRECT CONNECTION SET UPS??

Yeah, Chevrolet?
Fuel rail is on WRONG side

 

[68 HEMI GTS]

TimeSlips?

I’ve had several different carb setups on the car. This is with the vacuum operated six pack and a 4412 modified as a center carb.

 

[66Satellite47]

Yeah, Chevrolet?
Fuel rail is on WRONG side

I think those may be the carbs Direct Connection sold for a while, outboards have accelerator pumps for mech linkage & the different fuel bowls. Might be like the Corvette carbs?

 

[RM23M9A]

I’ve had several different carb setups on the car. This is with the vacuum operated six pack and a 4412 modified as a center carb.

View attachment 981673 View attachment 981674

Niice!

 

[68 HEMI GTS]

I think those may be the carbs Direct Connection sold for a while, outboards have accelerator pumps for mech linkage & the different fuel bowls. Might be like the Corvette carbs?

yes, those carbs don’t have idle adjustments. I added idle circuits to mine.. they are the bigger than the vette carbs and flow more than factory Chrysler vacuum outboards. Ford carbs had the drivers Inlet. Chevrolet’s are like Chrysler’s with the passenger inlet.

 

[RM23M9A]

If you "messed up" that process, I would destroy it. That's another reason why I got the Promax jetable outboard carb plates.
I just got these so I have 4 of each size of jets, plus some others for the center carb:
View attachment 967045 View attachment 967046
The Promax center carb metering block is fantastic too. Angled rear carb idle mixture screws were a given, as I too found a "workaround" but that was so cheesy and inaccurate...
Unless I have around $5K fall in my lap around the time I'm scraping together every dollar I can to finish my stroker build, I'm going to have to start out with my Promax modded Holley carbs on this Weiand intake, so maximum flexibility and ease of tuning is going to be critically important. View attachment 967040
Even now, with the 292°/.509 cam, headers, etc and using my Innovate Motorsports dual wideband O2 system I have benefited from the Promax mods.
Now if I happen to have the coin, I'll have what I consider the ULTIMATE 3x2 induction system, from F&B:
View attachment 967043 View attachment 967044

Beauty!!
Ive heard of these Promax baseplates with ANGLED screws? Where to find ONE?

 

[68 HEMI GTS]

Beauty!!
Ive heard of these Promax baseplates with ANGLED screws? Where to find ONE?

http://www.promaxcarbs.com/

 

[66Satellite47]

View attachment 981677

yes, those carbs don’t have idle adjustments. I added idle circuits to mine.. they are the bigger than the vette carbs and flow more than factory Chrysler vacuum outboards. Ford carbs had the drivers Inlet. Chevrolet’s are like Chrysler’s with the passenger inlet.

So those are the DC mechanical carbs? Do the outboards have larger venturis & throttle blades than the OEM outboards?

 

[68 HEMI GTS]

So those are the DC mechanical carbs? Do the outboards have larger venturis & throttle blades than the OEM outboards?

same size Venturi and throttle plates but they have a much less restrictive throttle shaft, they don’t use the sandwich style like the vacuum carbs.

 

[biomedtechguy]

Great posts guys.
Even when I install the 541 aluminum stroker, I'm committed, FULLY, FIRMLY committed to running a 3x2 setup, so all options and tricks are welcome.
As far as "do it yourself" jetable outboard plates, I’ll stick to medical equipment repair and service and just buy the stuff from Promax. They did parts and labor for me, and ran them and "pretuned" them on their dyno mule, which has the same cam my 440 has, and they run good. I need the professional help (possibly in more way than one )

 

[RM23M9A]

Interesting, Seemed easier for me to just pull plugs on the stock Mopar idle screws & turn them a bit, only took 1 try to get results I wanted. One or two tries on the idle opening screws. Never considered Chev base plates. We did think about trying to mod the jet plates for screw in jets, didn't seem like enough meat there & clearance in the passage. Might be wrong there.

Yeah, it works with the GM pickup module for E.Ignition?
Why not?