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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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Discussion Starter #1
I have a Edlebrock Avs 2 650 carb on my 351w and have got the idle circuit dialed in but I do not know a lot about carbs. My problem is it runs very rich when I’m doing normal driving, mostly in OD. When I get on the pedal slightly my afr will drop down to 11 and when I go on it about half way it’ll go to about 10.2. And when I’m on the pedal very little on a flat spot it’s about 12. Do I change the jets out for the primary’s for this or change the metering rod. Thanks for the answers.
 

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I don't have an A/F meter so I never attempted to tune mine. But I can tell you the model 1406 600 cfm carb has an excellent manual with half a dozen tuning pages and jet/rod combinations. I would suggest looking it up.

A 650 carb is probably too big for a 351.
 

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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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187 Posts
Discussion Starter #3
I don't have an A/F meter so I never attempted to tune mine. But I can tell you the model 1406 600 cfm carb has an excellent manual with half a dozen tuning pages and jet/rod combinations. I would suggest looking it up.

A 650 carb is probably too big for a 351.
You think it would be to big even though it’s not a stock engine. It’s got a much bigger cam, 185 afr heads, shortys and an edlebrock performer rpm intake manifold. If you still think that carb is to big what do you think would be good.
 

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I don't have an A/F meter so I never attempted to tune mine. But I can tell you the model 1406 600 cfm carb has an excellent manual with half a dozen tuning pages and jet/rod combinations. I would suggest looking it up.

A 650 carb is probably too big for a 351.
I ran a Holly 750 double pumper on my 74 Torino with a 351w. It was actually a little small to fully wake up the engine. I found the best combo was a triple power setup with 300 cfm carbs and velocity stacks.
 

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You think it would be to big even though it’s not a stock engine. It’s got a much bigger cam, 185 afr heads, shortys and an edlebrock performer rpm intake manifold. If you still think that carb is to big what do you think would be good.
Admittedly not a carb guru. I was just basing that off what I’ve read around the internet. I doubt it’s too big to function, perhaps it just requires leaning it out as you’ve already stated. I would dig up the manuals online because they look like they would make the rod/jet changes much simpler.
 

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Take a look at what I've attached and see if this helps get you to where you need to be.

 

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I agree likely too big, for 80% of the driving you are likely doing. Iis it too big for wide open throttle, no.
I do feel ilke you can tune it out though. I would change the primary and the metering rods.
Since you have a wideband it should be a ton easier to see what changes are doing what.

Dont overlook your igniton timing curve either, what is the base set at? Total, etc?? Lot of people don't fully tune the timing in, and compensate at the carb, at end up leaving power/driveability on the table.
 
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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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187 Posts
Discussion Starter #8
I do need to check timing and fine tune that because when we were setting it up I doubt we did it as good as we could. I’ll have to set a day aside for engine tuning.
 

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Get the manual. You can change the rods or jets and rods to lean it down. I have used these carbs for years. The manual will tell you what rods and jets go together. You will also need a jet and rod and spring kit.
 

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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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187 Posts
Discussion Starter #10
Get the manual. You can change the rods or jets and rods to lean it down. I have used these carbs for years. The manual will tell you what rods and jets go together. You will also need a jet and rod and spring kit.
I already have the tuning kit. And I’m guessing in the manual you are talking about the charts it shows. I looked at them but I don’t quite understand it.
 

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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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187 Posts
Discussion Starter #12
Can you take a picture of what you dont understand and I can help you with it.
172894

so I just don’t know which one to choose to get the numbers I want.
 

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If the carb is still set up like when it was new your settings are at one. Your cruise settings are up and down and the power is side to side. IF you want it lean while cruising you can go down to setting 19. The book will tell you what jet and rod to use to get that setting.If you want to lean it in cruise and power then select 16 17 or 20. The kit will allow you to use all the dark numbers. Hope this makes sense
 

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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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Discussion Starter #14
If the carb is still set up like when it was new your settings are at one. Your cruise settings are up and down and the power is side to side. IF you want it lean while cruising you can go down to setting 19. The book will tell you what jet and rod to use to get that setting.If you want to lean it in cruise and power then select 16 17 or 20. The kit will allow you to use all the dark numbers. Hope this makes sense
Yeah it does. I’ll probably go with 19. Also that allows me to not have to change the jets. A very easy swap.
 

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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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Discussion Starter #16
I did it and it worked very well. I get about 14.8 to 13.8 on the interstate.
 
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