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Discussion Starter #1 (Edited)
hey guys,

Let me start out by saying Im not writing this to bash Edelbrock. I have had a ton of fun with my 1407 carb and after calibrating and calibrating she was doing pretty good. I put about 11000 miles through her!

That being , I recently picked up a 750 cfm speed demon. It is duel feed and mechanical secondaries. I was told it had only been put on a motor for break in and then put on the shelf. It looked new and only set me back 150! Its a 520$ carb, wahoo! I purchased a rebuild kit and meticulously went through it, making note of every detail. I had no reason to believe the p/o wasnt telling the truth. It was all still stock specs.

So today she went on. I ditched the 1" open spacer for a 1" 4 hole spacer and also put on an electric choke kit. When you put on the electric choke you loose your secondary idle speed screw and replace it with a (low profile) set screw that mimics the screw but is a real pain to get to to adjust without first removing the choke. Unfortunately demons new carbs have the "idle eze" which mine doesnt have.

Right away the fuel line was leaking and I realized the duel feed line had a crack under the metal braid. After a 2hr search I was able to find a Russel duel feed line from a speed shop not to far away. I hate the red and blue fittings but itl do for now. ( no offense the colors just dont match anything I have)

Soon as I got home I raced to hook her up. She fired up right away and I adjusted the floats which were close already. I adjusted the fuel pressure regulator since these carbs like a lil more flow. I got the idle down slightly and evenly both primary and secondary. I then hooked up the vacuum gauge and adjust all 4 fuel air screws till I had 20 in hg. Thats 2in hg more than what I could get with the edelbrock and 1" open spacer. I know thats more vacuum then most you guys see but im only running a mild rv performance cam. One day that will get pulled for a lil more lift and duration @.50.

So once I was happy with the tune I took her out and I am absolutely shocked! Off idle stumble that I fought with is now completely gone. Throttle response is incredible. I have zero complaints so for with driving manners. I dont like that the vacuum port for the pcv is in back and a real pain to get to. I am not really happy with my universal throttle linkage and this 4150 style carb. Il have to buy something more suited for my carb. I do like the accelerator pump and linkage and how easy it is to adjust. I still have a pack of different size cams to try too. Right now the Pink, which is the largest I believe is in both primary and sec.

Anyway, I'm super happy with the outcome and even tho It took a ton more work than you'd think it should, if properly done, I cant believe how much crisper throttle response is. I believe the 4hole spacer helped too. I really do think swapping out the open hole spacer gave me a lil better low end feeling. To anyone considering swapping, just do your homework. There is so many different calibrating procedures but its very rewarding when you get her done and its so much better.

Just thought id tell ya that. lol wahoo:D
 

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Discussion Starter #3
true that

thanks corymon, im young and still soaking up info. I try to stay with good brands but at the same time not always choose the most popular choice. It sure is addicting, this whole car thing. :rolleyes:
 

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All the demons I have ever run have always had a super rich fuel curve. Not surprised the stumble is gone as edelbrocks are calibrated to run leaner. Did you notice a decrease in fuel mileage yet?

My 850 demon was a great carb AT the track but ran pig rich getting there:) if jetted for a 13.1 air fuel ratio at WOT it would run about 10-11 at cruise. Of course there are ways to help cure this buy it involves drilling metering blocks and jetting down the primary and messing with airbleeds which my demon did not have adjustable ones.
 

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what he said above is the truth,nite and day from eddy the demon but street driving eddy shines. if budget allows try ported spacer best of both worlds.
 

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Discussion Starter #6 (Edited)
All the demons I have ever run have always had a super rich fuel curve. Not surprised the stumble is gone as edelbrocks are calibrated to run leaner. Did you notice a decrease in fuel mileage yet?

My 850 demon was a great carb AT the track but ran pig rich getting there:) if jetted for a 13.1 air fuel ratio at WOT it would run about 10-11 at cruise. Of course there are ways to help cure this buy it involves drilling metering blocks and jetting down the primary and messing with airbleeds which my demon did not have adjustable ones.
I believe you altho I honestly believe I need more fuel at the top end of my primary circuit. I havnt had an afr gauge hooked up yet but it seems to be a lil flat untill the secondaries open. fuel mileage hasnt really gone one way or the other but I assumed it would cost a lil more.

I just purchased a box of jets and I want to get some various squirter sizes. I have the 31s on the pump squirters and I dont know if the numbers are equivalent to the eddys but i had 43s on my 1407. I dont know, I will definitely play around with it and this spring im going have an afr gauge hooked up.

What size squirters are you guys running? (on your 750cfm 4150 style, 355) Dont they say that both primary and secondary should be the same? It runs great at wide open throttle, and very smooth when just the primaries are open but I think it should pull a lil harder through the primary circuit.

Im just so happy I dont have to ride the clutch leaving in first anymore! And even the sound at isle has changed a lil which I believe is due to better fuel air atomization or whatever. lol
 
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