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Edelbrock Carb tuning
#1
So I admit I have not tinkered on 4BBL since 30+ years ago. Ok, so I have a new Edelbrock 4BBL on 351C, with 2V heads, but a 4V intake made for 2V heads. Car really runs good but was rich smelling. A local motorhead friend told me that with a cam I probably have a lower then normal vacuum. He said I should try a lower strength step up spring. I bought the 1840 Edelbrock carb tuning kit for my 1806 carb. I dropped down to the yellow 4"HG springs. Seemed to run just as well but not the rich fuel smell. So I tried blue 3"HG springs. Still no fuel smell, seems a tad less power. SO I need schooling. If I am only changing spring, no metering rod or jets, wouldnt it make engine produce "same HP" at cruise irregardless of spring? In other words, at idle I have less vacuum and need a lighter spring to keep metering rod down on leaner portion, but once I am running 50-60 mph I am up on same part of metering rod (richer) and so I should be getting same performance (HP) correct? I thought it felt a little less power but I can be imagining it too. Seems like spring would only effect transition from idle to cruise, but to affect overall mixture cruising I would need a different rod or jet, is that right?
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#2
Back in the day, the first thing we would change out are the metering jets.. Seems in your case, there is too much fuel supply at low rpm and the metering rods don't restrict fuel flow enough.. You've already played with the rod springs, so next step is to down size the jets. Not sure if Edlebrock has a multi size kit, or if you must purchase all the different jet sizes separately.. The key to fuel efficiency is air.. The more the better..

Hope this helps..

The person who says it cannot be done should not interrupt the person doing it. 
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#3
runninpony 
piper62j;269092 Wrote:Back in the day, the first thing we would change out are the metering jets.. Seems in your case, there is too much fuel supply at low rpm and the metering rods don't restrict fuel flow enough.. You've already played with the rod springs, so next step is to down size the jets. Not sure if Edlebrock has a multi size kit, or if you must purchase all the different jet sizes separately.. The key to fuel efficiency is air.. The more the better..

Hope this helps..

Yes, they have a tuning kit, with a set of springs, jets, and metering rods. Of course, I have to know what I am doing to use them lol!!!
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#4
do not jet the engine by fuel smell . jet it by performance and spark plug color . you also need to set the timing to the optimum curve first.

post a photo of both front spark plugs

if you have a big cam, you should get a multi fire ignition box like an msd .
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#5
Well I ventured and lo and behold, the PO had been there and changed both the metering rods and jets to a much richer stage. I put it back to stock where Edelbrock shipped it and what a difference. I will pull plugs after a bit and see how they are doing, but I am telling you everywhere I went people COMPLAINED of the fuel smell, it was that obvious. I understand about reading the plugs but this was like you could smell it from 50 ft away that it was not right.
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