I had same thing on my 6 bbl on my old 440. I put lighter springs in and problem seemed worse. I went with heavier spring and cleared up. If I recall what I read, is that the hesitation is perceived to be leaning out, so everyone says go lighter to get the outboards to open sooner. But in reality, its a rich bog, and a slight delay on outboards clears it up. I bought a kit that had something 5 or 6 different springs in it.

I have no data from A/F ratio to verify, only seat of the pants work. This was several years ago too. YMMV

I hope you mean one set at a time.

Do not mix and match springs, use the same color springs matched if your going that way.

6 pack on a 340, 440, or Hemi?

Mick,


usually most of the Holley re-issue carbs come with the black or brown springs, replace both springs at the same time, don't stagger their rating, IMHO if your experiencing a "hesitation" during the out board carbs coming on line it's because of the slow opening rate of the heavier springs, if you were experiencing a bog/break down during the transition then I'd say your opening too rapidly and need a heavier spring

Put the WHITE springs in and go up the color scale if you need more delay, and or higher RPM tip in, you need to know what's in your carbs before even operating them, I hope you put new plugs in the motor?, HEMI's run a bit lean on cylinders 5 and 6 running the six pack, your jet change may be for the good? but I'd read the cylinders after a few good runs on fresh plugs

Normally I'd recommend the clear sight plugs on the carbs fuel bowls, but the plugs are really sucking with today's plastics and today's gas, but I would buy a set and install them just to establish exactly were the running/idle fuel level is, generally I like to set the float level on all 3 carbs at the halfway point on the clear plastic float, then re-install the brass screws, don't leave the clear plugs in too long as they will soften/break off, when installing them, just finger tight

What have you done for a choke?

Mike

Mike,

I have 2 sets of springs on order, should be here soon. Just wanted to get it up and running, and see where it's at. Did the idle adjustment as you suggested, front is done, will switch it with the rear next. It needs it, idle speeds up on both sides when blocking the air bleeds on the rear carb.

I'll start with the white as you suggest. And have heard the same about the sight plugs, so I'll do that.

So what do you think of the 4.5 PV? Any chance that is part of my issue?

Haven't done anything with the choke. It's wired open for the moment. I'll either remove it, or install a cable as you suggested. You have a spare one?

Well the 4.5 PV should be OK, the stock set up would be the 6.5, But I understand the 4.5 based on your vacuum manifold baseline reading

But do get the fuel/air mixture ratios set up on all 3 carbs, fuel level, make sure your fuel pump is up to the task psi wise, double check the mechanical operation is 100%, then start playing/tuning the system out to what your motor needs, and you desire performance wise

I do have a spare cable for the choke set up, but you'll need to fabricate some linkage/bracketry unless you'd like me to do that for you?, just let me know

But I would recommend a functioning choke, up to you if you want a hand choke (that I can provide)or if you want to tinker with an electric set up of some kind

Mike

Speaking of PSI, what do Holley's like? I have the carter pump on there now with a pressure regulator set at 5.5-6psi.

I too live in Calyfornua where it seldom gets down to 40 degrees. Run no choke and when engine starts, has no tendency to stall out. Runs a Comp Cam roller, idle speed set about 800 rpm. If been parked a few days, hit the foot feed a couple of whacks before turning key. Always fires right off and settles right down. Car is factory V code, however running later Holly carbs as OP.

No hesitation when I floor it,,,just hang on and go. Love it. Hemi what?!!!

I got you on this one MikeM since I just went through my 440 six pack set up (for the umptienth time) and now I think I've got a good handle on it....thanks to guys here and over at FBBO.

Anway....

1. Your power valve is correct for your vacuum. I'm also running a 4.5 with 12" vacuum (I could go to a 5.5 since there's a teeny-tiny hesitation just off idle during acceleration).

2. Front/Rear springs should be the same.... the front/rear carbs are connected via the mechanical linkage anyway.

3. A "bog" is because the front/rear are opening too fast vs. the accelerator pump squirt in the center carb. Either put in stiffer/slower springs or increase the center carb accelerator pump squirt with a bigger pump cam, larger squirter + bigger pump cam, or change the existing white pump cam between "hole #1" and "hole #2". I can't remember which hole gives a bigger squirt.

4. Many people tell you to increase the center carb's jets & do a bunch of modifications to idle circuits, air bleeds, etc. I STRONGLY suggest that you start with the carbs completely stock & work from there. I un-did a bunch of these modifications I'd done in the past on my six pack and the car is MUCH faster with the carbs almost bone stock. I'm running #61 main jets at the suggestion of "Six Packs to Go" (I think that's their name) out in Albequerque, New Mexico. He's raced six packs for MANY years and knows his stuff. The only REAL way to be sure is to use oxygen sensors or get the car tuned on a dyno where they can measure your fuel mixture.... or track time.

5. Your cold stalling issue is definitely because you're not running the choke.

Install a wideband sensor and gauge on your car and check out whats actually happening with the air/fuel ratio. its the cheaper route

Or get an innovate LM2 from INNOVATE. get the dual sensor unit.

Anything else is guesswork....you are playing with a HEMI I think it would be a good thing to have...mistakes on air fuel ratio can be expensive on that engine!

got one.

well, I thought that if I put the full light one in the front, and the full heavy one in the rear, then if under full throttle the front of the car lifts, then I'll know the front one is correct, and if the rear of the car lifts, then I'll know the rear one is correct. Right? if the front is running correct, that should give the front cylinders power right away, so that will lift the front end, as that is where the power is coming from, and if the rear one is correct, the rear of the car will lift, as all the power is coming from the rear cylinders.

Should be a simple test, no?

You can also get some idle needles that you can adjust at an angle with a special tool (better and cheaper solutiuon that the Pro Form Baseplates with the angled needles).

Scott Smith at HARMS can probably tell u where to get them.

Goodbye to removing carbs. you can set your idle while the engine is running.

Did you type that with a straight face ...

I do not understand why people will not give you the proper help when they have the same information as many others.

If you read the guide you will learn:
A properly tuned six pak starts easily hot or cold.
The transition to the secondaries should be seamless.
If there is a bog - the bog is a LEAN bog.
The fuel levels are different that what has been suggested.
Use the carter street pump and 195 degree thermostat.


These do not apply to every build and maybe thats why its not so popular, might be good for a 275hp 340 or a 390 440 but all that crap dont apply to most situations.

Simple things like, not everyone runs a choke, a heat crossover, some cars never get over 180 degrees. Some run modified intakes, camshaft, rear gear, converter, personal driving habbits, already made modifications, compression,some run spacers...

Maybe in the all stock world those are things to live by but hardly in modified setting.

Mick - what are the results with the vacuum line hooked back up?

You still haven't answered the question unless I missed it,did you do anything with the jetting in the end carbs ? I would "assume" that if you have anything more than a cam with specs close to a sixpack cam,you would be lean as soon as you got into the throttle especially with a 540 cu in motor.

So are you liking the LM-2? Are you using the rpm module also? I am messing with the six bbl on a 512 wedge and have realized I need a wide band gauge. I have posted questions about wide bands on 2 different websites. The guys on here like the LM-2 but on the other forum nothing but bad reviews and they recommend the Daytona WEGO. How has your experience been?

well it seams like everyone has there 2 cents BUT that bog/hesitation you get when you start laying on the throttle and the seconardies are opening is a LEAN BOG, the secondary carbs have no accelerator pumps so when those 2x500cfm carbs open up at the same time, that engine is getting a lot of extra air and it takes a bit for the fuel to catch up(the reason your primary has an accelerator pump). putting heavier springs in the seconardies will slow them and make the transition smoother. I have an LM2 in my car to watch the Air/Fuel and you can watch it go lean for a slit second

Mick,


Whats the timing your set at, initial and total?, vacuum or mechanical?, I see vac in your pics, don't know if you changed out? points?, electronic/aftermarket


Mike