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six barrel tuning

ACME A12

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A lot of the big boys (F.A.S.T.) run the ProMax conversion kits which replace the fixed metering plates and allow for easy tuning of the outboard carbs. They also have a center base plate that lets you adjust the rear idle mixture screws without removing the rear carb. You can pick up plenty of good tuning tips over on the Lift Off Hood Playground since everyone there is running a six barrel set-up. Here's a link:

http://a12mopar.com/yabb/YaBB.pl


Here's some info on the ProMax metering plates:

http://www.moparmusclemagazine.com/tech ... index.html

You can always contact Bob K and ask him too. After 40+ years he's got it pretty well figured out...

Ray
 

moparstuart

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ACME A12 said:
A lot of the big boys (F.A.S.T.) run the ProMax conversion kits which replace the fixed metering plates and allow for easy tuning of the outboard carbs. They also have a center base plate that lets you adjust the rear idle mixture screws without removing the rear carb. You can pick up plenty of good tuning tips over on the Lift Off Hood Playground since everyone there is running a six barrel set-up. Here's a link:

http://a12mopar.com/yabb/YaBB.pl


Here's some info on the ProMax metering plates:

http://www.moparmusclemagazine.com/tech ... index.html

You can always contact Bob K and ask him too. After 40+ years he's got it pretty well figured out...

Ray
how about these monster I put on my 69 charger
 

mac

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here is some good reading

http://sixpacksixbbl.homestead.com/mrsixpack.html

i have been on the quest for a good running 6 bbl motor for years and what i seem to find out is that the closer you come to the stock settings the happier you will be. critical areas are float bowl settings, proper power valve, proper jetting(do not over jet), the right springs and a good ignition curve.
 

ACME A12

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moparstuart said:
how about these monster I put on my 69 charger

Looks to me like of the three components necessary for the successful operation of an internal combustion engine - you are definitely missing two...and maybe have the third... :lmao:
 

3BIRDS1X

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Here's a copy and paste from a recent moparts thread it sounded good so I saved it in case I ever needed it (probally never will but you never know) can't give credit to the author as I didn't save that part


Here is a guide to tune six packs. It's not everything but gets you close enough.

Quality cap rotor, wires and plugs that are not too hot or cold in heat range.
Distributor vacuum port on carb disconnected and plugged
Make sure that your ignition advance curve is such that you can run at 15 - 18 deg advance at idle. This is important.
Car in neutral-auto or 4 sp, emergency brake set
A good quality vacuum gage is required, a digital tach if you have that as well.
Connect vac gauge to manifold vacuum source.

Outboards idle adj screws out 1/8 turn ccw THIS IS IMPORTANT

64 jets in ctr carb

If you have new carbs(untouched) they will have 62 jets in the center carb

Black springs in the secondaries
You must know what power valve is in the ctr carb. Typically a 6.5

The slotted screw on top of the float adjuster, is just a lock screw, you can remove it for now, the 5/8" nut is the adjuster/needle seat nut, rotating it counter clockwise will raise fuel level in the bowl, clockwise will lower it
Make small 1/2 turns & let the car run a 3 or more minutes so the fuel levels off
check the fuel in the clear site window, at the bottom on the ctr carb and up to half the window the front and rear carbs,

After you set the fuel level in all 3 carbs, reset the idle on the center carb


Floats are adjusted properly
Ctr carb bottom of the sight hole
end carbs a very slight trickle out the sight hole

Starting point for Jets. center 65, front 78, rear 80. If the weather gets cold you might want to increase that to center 66, front 80, rear 82

Check the center carb and be sure to adjust the idle screw until the throttle blades are closed and the transfer slot is exposed no larger than a square. [carb would have to be off the car to see this]
You only want about .040" of the transfer slots exposed below the throttle plates.
If the idle screw is adjusted too high, you will be into the transition circuit, exposing too much of the vertical rectangular slot. Many times the idle screw is adjusted incorrectly to compensate for other issues. This puts the carb into the transition circuit and at that point you have no mixture control on the center carb.

Start car, set idle to 1000 rpm and allow engine to reach operating temp. 195 degree thermostat required or fuel will puddle in the intake. This is a must.

If the car won’t idle: Is engine vacuum reading at least 2 hg higher than the power valve rating?
This must be correct this before proceeding If ok proceed, if not correct power valve issue and proceed. Note some engines only pull 5 hg of vacuum

Now set the initial timing to where it wants to be. Somewhere between 10-20 degrees BTDC. The engine will tell you by increasing vacuum and rpm at this point. In some applications the engine does not care, so set it to 12 degrees BTDC.
Cams with 106-degree ctrlines seem to like initial timing set at 15-22 BTDC
Cams with 108-degree ctrlines seem to like initial timing set at 12-18 BTDC
Cams with 110-112 degree ctrlines seem to like initial timing set at 8-12 BTDC
center carb idle mixture screws out ccw 1.5 turns

Re-Set the rpm for 900-See if you have "control" over the idle mixture screws on the ctr carb. Using a good vacuum gage adj mixture to highest reading of vacuum. If you do not have control over the idle mixture you have issues that need to be taken care of before proceeding. Issues such as poor intake sealing, the wrong pcv valve, a vacuum leak from the brake booster or other places, wrong pwr valve etc.

Recheck idle rpm and set to 900
Drive car. Is the car rich? Jet down 2 steps until you find the min jet size. You will know when you are lean, no power.

Most times you are over jetted.... Do not over jet!

Now reset the initial timing again. Somewhere between 10-20 degrees BTDC. The engine will tell you by increasing vacuum and rpm at this point. In some applications the engine does not care, so set it to 15 degrees BTDC.

Re-Set the rpm for 900-See if you have "control" over the idle mixture screws. Using a good vacuum gage adj mixture to highest reading of vacuum.

Recheck idle rpm and set to 900

How do you know when you are "there”?
You should be able to idle most cars down to 800-900 rpm in neutral and the response is crisp. You do not smell raw gas in the exhaust. The bottom of the intake is not soaked with fuel. The spark plugs are clean. The car starts runs and drives smoothly when cold. The car restarts immediately when hot without touching the throttle. When you whack the throttle from an idle the engine immediately returns to idle.

Note: If your initial timing exceeds 12 degrees BTDC with a MP distributor typically you need to modify the advance curve so the total timing is not more than 34 degrees BTDC.









think the "theory of operation" needs to be reviewed

A six pak engine runs on the center carb and idles on all 3. The center carb is 450 cfm which means it has plenty of flow up till about 4000 rpm where the secondaries come in and take care of the work. The idles circuit in the outboards is always contributing air and fuel to the mix.

The center carb needs to be set up properly first and then the secondaries dialed in.
Whacking the throttle at idle to get the secondaries to open is pointless and useless as it indicates nothing other than a lack of understanding. Black springs in the secondaries is not a misprint, but good advice, if you have not tried the advice I suggest you do.

A properly tuned six pak will out run anything other than a properly tuned heeemi [sic] and then it better had be a stout heeemi as i have beat up more than several of the manly heemis with a six pak over the years.


This is not rocket science and the document provided is culminated from lots of peoples input.
Print the document and go tune your cars and please report back.
 

ACME A12

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I saw a mention of this thread over on the LOH Playground. The comments that I saw indicated that it offered some good info and was a good starting point.
 

joewhite440

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Someone else my have posted?

Here you go... Saved from previous 6-pack posts

macmic87-Moparts
here is some advice given to by another moparts member. a little lengthy, but if done in order makes a difference.

have to agree strongly with Mike(HPMike) I've been running six pack inductions for about 30 years now, sm blk, big blk, and even the custom 6 pak cast HEMI intake manifolds that I made for the 71 wingcars,.....I don't have anything but, sixpack cars,,,,,,,,I've rebuilt countless numbers of carbs, along with countless installations and tunings,....when there are troubles, it usally due to someone unfamilar with there tuning or functions, or attempts at trying to improve them,......which usally results in "problem" carbs, starting, stalling, flooding issuse!.....seeing your have "new" carbs/ set-uo,....I'd recommend you use a Carter street pump, don't use rubber hose, it's problems down the road!, use a factory style/ repro steel, or stainless steel fuel line kit,a good quality hi flow fuel filter, AFTER the pump!, not before!, you'll restrict the fuel flow, Factory style linkage, no junk progrssive/ mech linkage!, change out the brass side float screw on the fuel bowls (all 3 bowls) with Holleys clear sight plugs, this way you can see your float level, and no gas spills trying to adjust, their like $4 each,.....when setting the fuel level, I've found that it's best to bring it up to half the height of the clear sight plug, (can't do this with the brass sight screw!, unless you have X-ray vision, hence the need to install the clear plastic sights).....plus "if" you ever have a starting problem, just shaking the car side to side will slosh the fuel in the clear site, and you'll know wether or not you have fuel in the bowl,....after you have basically installed the set-up, and started the car, and set an acceptable idle after warm up, with the engine running, set the floats, start with the center carb, the slotted screw on top of the float adjuster, is just a lock screw, you can remove it for now, the 5/8" nut is the adjuster/needle seat nut, rotating it counter clockwise will raise fuel level in the bowl, clockwise will lower it, make small 1/2 turns let the car run a bit, check the fuel in the clear site window, half the window is ideal height, esp. in the front and rear carbs, when they dump in, you don't wanna lean the engine, which on a sixpack car, might "melt" a piston or two!....really!, been, there, done that!....after you set the fuel level in all 3 carbs, reset the idle on the center carb, by disconnecting the linkage on the end carbs, if your using an idle solenoid, make sure it's energized in the up position contacting the center carbs solenoid idle arm screw, set the desired idle, that keeps your car running, factory specs are a guide line, your cam, vacumm, etc, will affect your desired RPM range, after you establish this idle, this is what your car will run with, now de-energize the solenoid, using the idle srew located on the ceter carbs main throttle shaft, set the idle to a bare minimum running idle, this is were your throttle shaft will close down too when you shut off the car, and the idle solenoid de-energizes, if later you have shut down problems of the car desieling, (sputtering run on after shut down) keep lowering the idle screw on the center carb main shaft, untill this is condition is eliminated, the idle solenoid was added to maintain an idle, and allow the throttle blade to choke off the engine on shutdown if needed, when it de-energized, after your center card idle is set, now comes the fun, start the car, in idle, the front and rear carbs are still disconnected at their main throttle linkage, (important note: make sure no vacumm source is hooked up to the front and rear carbs when main linkage is disconnected, cause any reving you may do, might tip in a end carb! with vacumm!, and if you can't shut it down in time, you might lose an engine!....seen it done!)to properly set the fuel/ air mixture idle screws, start with the center carb, hook up a tach.......warmed up, good idle (low)....turn the fuel/ air mixture screws (2) located on each side of the center carb metering block, do one at a time, run it in slowly, until the engine begins to stumble, slowy back it out watching the tach needle, stop when you've obtained the highest rpm reading,....you can also do this with a vacumm gauge attached to MANIFOLD vacumm, I like to use both at the same time, ...repeat the process for the other side, when done, now re-do-it, again, just to confirm settings, now some of the end carbs, have their fuel idle screws "plugged" with lead, they are located in the base, in the front of the carb base plate, under the bowl, if plugged, dig out lead plug, most people think ones for fuel, ones for air , their not!, you'll adjust these screws just like the center carb, except you can't just use a vacumm/ tach gauge,....look into the top of the front end carb, you see 2 small projections in each bore on each side, just below the neck, these are the air bleeds, block off the outer bleed using your finger over the small tiny hole, with the motor running at idle (low), it should stumble or pick up in idle, when you block off, either outboard bleed, set the front carb first, pick a bore, left or right, with it's coresponding baseplate idle screw, block the bleed off with your finger,(make sure the carbs throttle plate is fully closed) do one side at a time, when you block the bleed, if the idle increases, too much fuel, remove your finger, turn the base screw on the side your blocking the bleed on, in, one turn, block the bleed again, listen for the idle, (you could use a tach gauge at this point), if it stumbles/ decreases, no fuel, back the base screw off a half turn, block the air bleed again see where the "idle" is,......keep adjusting in this fashion until there's no change in idle, no increase/ decrease, you now have the ideal fuel/ air ratio for the vacummm requirement on your motor, complete this for both sides of the front carb, shut off the motor, disconnect this carb remove it, re-install it in the rear,....install the rear carb, now in the front, adjust this carb like you did to the last one, after you hook up everything, now here's when most guys will balk at this move,....they'll insist the air/fuel mixture won't be 100% by moving the tuned front carb to the rear, well if your truly familiar with the sixpack set-up, you know getting to the rear carbs base screws is fustrating to say the least, unless your squeezeing every ounze of effeciency out of the motor, this technique is far better than leaving the factory setting/ lead plugs in, with is usally a lean set-up,,,,,,, after setting this relocated carb up, if you wish you can "play" trying to "tweak" the rear carb, this may include a round of removal the "tweak" the screws to obtain that last ounze of "tuning", I've yet to see a "tool", truly capable of fitting into the installed rear carbs "idle screws"......anybody?,

Well, when your "done" setting the air/ fuel "idle" mixtures on the end carbs, connect the end linkages, to the end carbs, do it with the idle solenoid energized, the rods are threaded were they join together on the center carb, they install on the end carbs with rod clips, there is a F/R or left?right handed clip, energize solenoid, do the front carb first, make sure the linkage is pulled far forward on the center carb secondary rail, thread the rod, in or out, until it fits nicely in the hole, then proceed to the rear, repeat this proceedure, now check the linkage for any binding, you should be able to chrack open (engine off!) the center car, WOT, and manually open both carbs by rotating the front carb throttle arm, close the center carb, check all linkage for binding, readjust if needed, now de-energize the idle solenoid, see if any bind is preventing the center carb from closing on the main throttle shaft idle screw, you may have to comprimise on some idle/ and or end carb linkage adjustments to have an ideal, functioning set-up, but once you take the time to do this, you'll appreciate your efforts!,....as far as altering the end carb secondary springs in the vacumm pods,.....I like a sixpack to come in quick,....you'll have to buy 2 sping kits, replace with the "white" springs if you want a quick responding set-up,....if you what a mid range set-up use the "yellow" springs,.....any thing in the brown or black range is worthless.,,,,,Hell I could write a book here, I probally have, if you have any other questions, PM me.......I wrote this for others, to utilize as well,.......

--------------------
A True Hybrid: Burns Gas AND Rubber!
 

mac

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that guy macmic87 is me. :lol:

anyway i just did some more tuning of my six bbl and i think i just about have it. this is after another phone call with mr. sixpack Bob K. (great guy to talk to)

it all boils down to trying to keep it simple which is not one of my better traits. mostly it is all about fuel management. don't have too much fuel pressure (7 psi). have all float bowls adjusted and double checked (critical). make sure the outboard carbs are adjusted for idle mixture(also critical). make sure center carb is adjusted for idle mixture (with a vacuum gauge). a good timing curve that is confirmed (i run no vacuum advance). if car is basically stock do not over jet. and don't be afraid to change outboard carb springs. my engine after the last cam change had very good vacuum and i had to put a relatively stiff spring to get things to work right under load.

i finally have a car that won't fall on its face when i mash the pedal. :drive: :drive: :drive: :drive:
 

ACME A12

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I was snooping around on the promax website. The billet metering plates for the outboard cards are $150 for the pair. Includes the blue gaskets and new screws. That's not bad for what you get IMHO. The billet baseplate for the center carb runs $175.

I'm going to be running a set-up fairly close to stock (no big cam - just the Mr. Sixpack with 1.6 rockers) so I'm sure that I can get away without the ProMax stuff, but the adjustibility and ease of access sure has me thinking about these upgrades... I was planning on sending my carbs to Harms...wonder if he'd balk at installing them during the refurb...? No sense having him charge me for a center baseplate (if mine turned out to be warped) if I'm not going to run a stocker anyway...
 

mac

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ray, take a look at quick fuel carbs. they have a metering plate for about half the price and they are the ones i am currently using. part #34-3. i also use the base plate fpr the rear carb and it does make things a whole lot easier.
 

ACME A12

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mac said:
ray, take a look at quick fuel carbs. they have a metering plate for about half the price and they are the ones i am currently using. part #34-3. i also use the base plate fpr the rear carb and it does make things a whole lot easier.


Mac, I'm gonna assume that you meant center carb and not rear carb regarding the base plate. Did you have the Quick Fuel set-up installed when you were running the Lunati and what did you end up with for jets after you switched to the Mr. Sixpack camshaft?
 

mac

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i did mean rear carb. i bought the carb base that has the idle metering screws facing at an angle to allow you to adjust with the carb on the engine.

i had the quick fuel metering plates on with both cams and ended up with #66 in the center and # 77 on the passenger side and #80 on the drivers side as per mr six pack. also ended up with the brown springs in the secondaries and the car is very happy. :drive:
6143799-macmic87burnout1.gif
 
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