Tuning
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Junior User
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From: Bonne Terre,Mo 63628
Tuning
I just installed my Holley 670 street avenger carb on my 390. I have adjusted the floats and adjusted the air fuel mix at the highest vacuum i could get. I don't have a tack yet, so idle is set at how it sounds. It seems when i try to set the secondaries float i have to drive it around before it levels out ( looking trough the clear sight plugs) does any one have any tricks to fine tuning this carb?.
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Junior User
Joined: Nov 2007
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From: Bonne Terre,Mo 63628
it is new out of the box. It said something about i might have to change the jets,? to a different size, i live in missouri, so sea level, what about atmospheric pressure. I also put a edl performer rpm intake on, right now i not to impressed with how it performs, and a rv cam.
Lead Driver
Joined: Jan 2003
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From: Ohio
Only know one friend that has an Avenger carb and he's not impressed with it either.
There is ALOT of tuning available to you and how far you take it is up to you. Jet changes will allow you to change how rich it runs down the road. Drive it some, pull the plugs. Are they black/sooty or white/clean?
The accelerator pump changes the shot of fuel that aides in getting truck to take off without stumbling.
The secondaries are pulling alot of fuel at idle so the fuel level does not adjust as quick when you move the needle/seat adjustment. If you start LOW, then as you move it up it will change as fuel comes in. Going the other way, it has to use the fuel that is in the bowl, which is why you have to drive it some. With a vacuum secondary carb, I'll pull the pin on the linkage so I can manually open the secondaries to let it use some fuel.
There is ALOT of tuning available to you and how far you take it is up to you. Jet changes will allow you to change how rich it runs down the road. Drive it some, pull the plugs. Are they black/sooty or white/clean?
The accelerator pump changes the shot of fuel that aides in getting truck to take off without stumbling.
The secondaries are pulling alot of fuel at idle so the fuel level does not adjust as quick when you move the needle/seat adjustment. If you start LOW, then as you move it up it will change as fuel comes in. Going the other way, it has to use the fuel that is in the bowl, which is why you have to drive it some. With a vacuum secondary carb, I'll pull the pin on the linkage so I can manually open the secondaries to let it use some fuel.
Last edited by Freightrain; Jan 28, 2008 at 09:08 AM.
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In my experiences with holly wich is what i prefer Ive noticed that after some adjustments it can take them a bit of time to settle in or down I know this sounds nuts since ther more of a simple design but there are a few racers that agree with me and we've had our disscussions about it. I will admit Ive never played with the avenger series though I like the old dble pump style. After some tuning and slight mods I get 12mpg city and 14-17 hiway in 4500lb truck with a 390. PM me if you need specific help with it.
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