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6 pack fine tuning/jetting recommendations

Posted By: mopeman

6 pack fine tuning/jetting recommendations - 08/15/09 02:12 AM

OK, so I got the carbs running good, used a tach and vac guage to tune the carbs, did the front to rear carb swap too. Replaced the secondary spings and worked all the way down to the white springs and still have a bog/hesitation when the outboards kick in. I will be getting the Promax jet blocks in a couple of months when I can afford them. So in the mean time, I will try to drill out the factory metering blocks. I don't care about the blocks because I will be replacing them, but I don't want mess them up and not be able to enjoy the car untill I get the Promax plates. So I will be sneaking up on what I need. Does anybody have any ideas or recommendations for this. I know even though the car runs great, it isn't good for the engine to have the hesitation.
Posted By: macmic87

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 02:46 AM

you say you are using the white spring. that is the lightest spring. if you are trying to smooth the transition of the outboards coming in, you should be going in the other direction. purple then plain then brown.
Posted By: mopeman

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 02:55 AM

Forgot to mention, I changed out the center carb jets and went to 68's. The 440 spec's are .060 over bore, .509 lift old school MP cam, 2.14 intake and 1.81 exhaust valves, 906 heads full port and polish job, large tube TTI headers, thin head gaskets and the 6 pack...
Posted By: 340SHORTY

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 04:22 AM

with the lack of vacume that the .509 cam makes you will never get them right. they need vacume to work,, the more the better.....
Posted By: BergmanAutoCraft

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 10:15 AM

You really need a wide band O2 to see whats going on. The last 2 setups I did needed the outboards slowed down with stiffer springs not lighter.
Posted By: fastnos

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 11:07 AM

With out being able to see in real time what its doing without a wide band O2 to reall "know" what you need its a guessing game. If I was just curious enough I might try to play with the ACCelerator shot, and even might go up to the 50cc shot pump. you might be able to give it a longer shot just with the acc linkage on the pump. But it still would be best to Beg, Borrow, or Steal a wide band O2. Not sure, but can you check with Autozone, Advance, or any of your local parts store to see if they have one in their "Loaner" tools section? (just a wide shot in the dark, but they might!)
Posted By: 3twos

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 01:54 PM

Quote:

With out being able to see in real time what its doing without a wide band O2 to reall "know" what you need its a guessing game. If I was just curious enough I might try to play with the ACCelerator shot, and even might go up to the 50cc shot pump. you might be able to give it a longer shot just with the acc linkage on the pump. But it still would be best to Beg, Borrow, or Steal a wide band O2. Not sure, but can you check with Autozone, Advance, or any of your local parts store to see if they have one in their "Loaner" tools section? (just a wide shot in the dark, but they might!)




Changing to the 50cc pump would not hurt at all and also you could try changing the squirter in the center carb to something like a # 35
Posted By: aarcuda

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 02:03 PM

white springs or the plain springs? the look the same color wise (oxidation) but are much different

my setup is 64 centers, 84's outs (promax jet plates) (68's are way too rich), plain springs, 50 cc pump, white cam, 32 squirter
Posted By: Crizila

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 03:33 PM

Go on to Promax's web sight. They have a lot of good recommendations for many different scenarios. Pick one that comes closest to your set up. Also, run the fuel levels in the end carbs about 1/2 way up the sight glasses
Posted By: aarcuda

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 06:48 PM

Quote:

Go on to Promax's web sight. They have a lot of good recommendations for many different scenarios. Pick one that comes closest to your set up. Also, run the fuel levels in the end carbs about 1/2 way up the sight glasses



whats the link? i couldnt find anything on their site
Posted By: Dave Watt

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 06:51 PM

The bog could also be in the distributor advance curve, too fast or too slow will make it bog at the hit of the throttle. If it is a box stock electronic distributor, it's probably too slow.
Posted By: Crizila

Re: 6 pack fine tuning/jetting recommendations - 08/15/09 07:54 PM

Quote:

Quote:

Go on to Promax's web sight. They have a lot of good recommendations for many different scenarios. Pick one that comes closest to your set up. Also, run the fuel levels in the end carbs about 1/2 way up the sight glasses



whats the link? i couldnt find anything on their site

http://www.mopar1.us/6barreltips.html
Posted By: mopeman

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 03:29 PM

OK, an update...when I first got the carbs the yellow springs were installed by Holley. After the first run and a pretty good bog I dropped down to the short yellow and the same thing happened, then the white springs went in and same thing maybe a little worse. Felt pretty cool went the outboards did kick in, but I knew it wasn't good for the motor. For some weird reason I never thought about going the other way with the springs, every post I read said to go to the lower springs. Well after the first reply (thanks macmic87) I went out a put in the purple springs and it was a heck of a lot better! The transition was alot smoother and the outoards were'nt crashing in. So now I have the brown springs in, and there is just a slight ssssssststudder. I will try the black today and see what happens. Maybe it will be gone, but if it isn't, I'll be back....
Posted By: lokalik

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 03:34 PM

if you using the stock #31 squiter try the 33 or the 35.
Posted By: mrmopardan

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 05:40 PM

I have almost the same set up as you, but edelbrock rpm heads. I run the .509 also. I use .35 squirter 50cc acc. pump with browm pump cam and brown springs in the end carbs. Center carb has #64 jets. Drilled out the end carb metering plates with .099 drill bit (or #84 square jetting) I have no bog now & the car runs like a scalded ape . BTW the end carbs operate on ventura vacuum not engine vacuum.
Posted By: aarcuda

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 05:43 PM

Quote:

I have almost the same set up as you, but edelbrock rpm heads. I run the .509 also. I use .35 squirter 50cc acc. pump with browm pump cam and brown springs in the end carbs. Center carb has #64 jets. Drilled out the end carb metering plates with .099 drill bit (or #84 square jetting) I have no bog now & the car runs like a scalded ape . BTW the end carbs operate on ventura vacuum not engine vacuum.



I have almost the same setup on my 416. bigger cam though. everything is the same except i have the purple springs in the outs
Posted By: mopeman

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 06:09 PM

So do you think the 68's are too much...it seems to like it? I have a 50cc pump kit for a 4150 DP I never installed, will it fit the 2BBL center carb? I'll have to see what size squirter I have, are the 31's stock?
Posted By: aarcuda

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 07:51 PM

66 was too much for me so i'd say ya, 68 is too big.

and yes, the 50cc pump will fit
Posted By: macmic87

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 08:18 PM

glad it is coming together. i would try some smaller jets than the 68 in the center. i am currently running 65 center 82 front and 84 rear. but of course every one is a little different. just do one change at a time to make sure of the effect it will have. don't for example change the center jets and change the accelerator squirt size. one at a time and run it.
Posted By: mopeman

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 08:28 PM

After the yard work, I will put the black springs in and see if there is a change, if none, I will put the brown springs back in. Then I will mess with the jetting alittle. Then mess with the acc pump and install the 50cc pump. Oh I love tuning my car...
Posted By: 70sixpkrt

Re: 6 pack fine tuning/jetting recommendations - 08/16/09 09:29 PM

I am running 65s in my center carb with the Promax metering plate. On my outboards, I am running 80s on all fours with the Promax jettable plates. I was running 84s but that was way rich.
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