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.