Just bigger holes in squirters. carb had 34's in it i put 43's. Rod is back in middl;e hole stumble is gone. It just gives a little more fuel when it squirts. So yes more volume. Tech guy was right.

Well, I finally got to spend some time on the car this weekend. I got the Edelbrock calibration kit out, and put the jets back to the stock size, drilled out the pump nozzles to .040, used metering rods to go one step rich, and bumped my timing 5 degrees, The stumble is 95% gone!

I think with some more experimentation with the springs and maybe go to the .043 nozzles it will be completely gone.
I am now very happy with the way the car runs, and thanks again to all who posted.

1 - Edelbrock 1407 750cfm New from Summit - $259
2 - Squirters/Nozzle Kit - $23.50
3 - Calibration Kit - $46.75
4 - On the phone with Edelbrock tech guy - I get my free 43 squirter in the mail a week later , but i already told them i tried that route/bought nozzles (Read all my earlier posts)
5 - Top Hole in plunger gives you the most volume , lower holes give you a faster/quicker shot of fuel
6 - Drill this Drill that blah blah blah
7 - Countless hours working on carb and money spent
8 - Try different 4 hole spacers / Open spacers blah blah blah - Hell i spent more money on tax and or shipping charges


1 - Edelbrock 1412 800cfm New at Summit $299
PRICELESS

Sold my 1407 on Ebay - Edelbrock and many others on this forum said try the 800 series , you will love the difference

Performance out of the box - PRICELESS
Plug color PERFECT - Stumble NO
And i still have all the springs/nozzles/calibration kit if i still need it

Funny thing is , you think you have it fixed , and running good (And yes i also had mine about 95% fixed , and most of that time was trying to get some decent plug color , carb was so damn lean out of the box brand new , i think i went 12% richer across the board to get some color on my plugs , but still wasnt good enough after countless hours and money spent) , until you bolt something else on that actually PERFORMS AND RUNS PERFECT - The Holley 3310 that i had/tried/laying around ran flawless also - I wanted to reach that performance level with the 1407 - HA HA HA
UNTIL I BOLTED ON THE EDELBROCK 1412 OUT OF THE BOX

You dont know what you got until its gone - Yep i miss it like my ex

I bought a brand new 800 Thunder AVS. Car has a big cam. It had the same stumble problem. Put 43 squirters in it runs fine now. Even the 800's have a stumble problem with big cam motors. There fine out of the box on a stock motor.

I HAD THE SAME PROBLEM on my mild 440
after chasing it for 1 year and trying 3 diffrent carbs including demon and holley and edelbrock which did the best i found it to be a intake manfold problem. i had oringaly blocked the heat crossovers on my ch4b and it caused the fuel to not atomise. i took the crossover block out and havent had ANY problems sense. so if its blocked fix it. old man mopar wouldn't have a heat crossover if he dident need it.

is the problem worse with a cold engine if so it means it gets better with heat. so heat the intake!!!!!

The biggest problems with those carbs is the weighted flap in back, and its non adjustable other than grinding!. the 800 works well cause it has a adjustable flap just like the q-jets!...

what flap are you refering to?

ok not really a flap ,but its weighted and usually it is too heavy and flips open to fast or not fast enough causing a stumble.. By Grinding off some weight of it u can control it better, but it takes some guess work pretty much, just easier to get a 800 avs as that is adjustable

I'm glad to hear you've got it fixed. I agree on the lean condition but I'm not entirely convinced of the way of fixing it. What I do is ar a warm idle, shut the engine off, count to 5 (or 10, doesn't matter) and turn the key to crank it. If it doesn't start right up without touching the throttle, the idle isn't rich enough. You should be able to richen the idle via the screws until the idle suffers, if you can't do that you need to richen the primary jet/rod combo. Believe it or not, that affects the range of the idle mix adjustment. What happens is, if the idle is lean, all that lean mix in the intake is sucked into the cylinders immediately when you crack the throttle. The accel. pump circuit is there to richen the sudden rush of air through the carb, not fatten up the mixture already in tne intake. That said, a big squirt can help cover up the other problem. If your primary mix is lean it'll be weak after the pump shot has passed and power and mileage will suffer because you'll need more throttle to accelerate the way you want. Also, a big squirt will waste fuel if it isn't really needed once the rest of the fuel curve is dialed in.

Quote:

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I listened to the Edelbrock tech guy and installed the 43 squirters. Put back the stock jets and rods. Stumble is gone. Runs super. Went with yellow springs as i have just barely 10 inches of vac at idle in park. They were right, off idle stumble is a lean condition, needs more squirter. I guess thats why they have a tech line.

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My idle is plenty rich. I can wait 20 mins and hit the key with no throttle and it fire's right up. Did move up to the orange springs. Car is running super.

I never had a stumble when secondaries opened only at tip in off idle. I have an 800 thunder and was going to play with that adjustment. Haven't really looked at it to see how it adjusts. Maybe get a little more power. Bought the carb new but it came with performer series owners manuel?????? That's not adjustable on a performer carb. I'll be looking into that tomorrow and see if i can figure it out. Yes i have a thunder not mistaken performer.

my 600 has a little .1"x.1"x.25" chunk of metal (the weight) sitting on top of the check valve. I put it back in when I drilled out the nozzles to .040, and I still have a little off idle stumble w/the acc pump set to the inside hole, so I'm going to pull it back out tonight and see if that takes care of it.

Not to bring up a REALLY OLD thread but I just fixed my hesistation 650 AVS, with combination of Edelbrock PN# 1468 (800 AVS Accelerator pump), 2 turns on the air valve and some non-ethanol fuel. I also had a vacuum leak at the front vacuum port connection which was fixed with a hose clamp.

Plenty of the N/SS cars run 2 850 Holleys.
There are 4 of us in N/SS with similar combos as far as weight, cylinder head, cam , etc. They run 9.50 or 9.75 index with the Holleys. I'm the only one that still runs Eddy 750's. I run the 9.25 index. Car has been 1.29,9.12@147.7. Carbs are box stock with the chokes removed and rejeted. Squirters are stock.
Doug

From what you said, tightening up the airdoor may have been the key.

R.

I tried anywhere from 1.5 turns-3.5 turns, all which did not resolve the bog, until I swapped in the 1468 Accelerator pump. I started at 1.5 turns, had very small blip but much smaller than before. Tighten it the air door down to 2 turns and bog went away. Then I put in non-ethanol 92, not sure if that actually helped the situation but it felt like I added more responsiveness and ran much smoother throughout the powerband.

What's different about the accelerator pump? I thought they were mostly interchangeable.

R.

The bottom one is the 1468 Accelerator Pump Assembly. The Spring is wound much firmer.