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Discussion Starter #1
I finally gave up on my Edel 1407 carb because I couldn't fix the off idle stumble at the starting line when going to WOT. I tried every metering rod/jet changes, adjusted the accel pump, etc. and it never improved. I then bought the Speed Demon 750 mech/double pumper and dropped the mains and secondaries 2 sizes and ran that at the track. Here's the results:
Edelbrock 1407:
60': 2.036
1/8th: [email protected]
1/4: [email protected]
street tires, no consistency
Demon:
60': 1.907
1/8th: [email protected]
1/4: [email protected]
street tires, very consistent
I literally bolted that carb on and picked up over .2 sec. I raced 5 times that night in similar conditions (I"ve got 25 runs on that Edel setup in every condition) and ran between 12.75-12.85 with one 13.1 when I blew the launch. I'm running street tires so that's a lot more consistent than the 1407 setup where I would have a .5 sec range on a typical night. I just don't think the 1407's can deliver enough fuel on the bottom end when racing with a modified motor with the vac secondaries, I guess live and learn.
 

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On the 351?????

I'm sure youre tired of hearing this........unless you have 4.56 gears and a cam that matches, a 750 is just too big
 

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Discussion Starter #3
Interesting you say that, Edelbrock Performer RPM package that I'm running recommends the 750 cfm carb when running their heads/intake/cam w/ headers. I was just following directions /forums/images/icons/smile.gif
 

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Those are good et's though!!!! /forums/images/icons/smile.gif
 
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When you use a mech sec double pump carb, You do not size it the same way as a vac sec carb. In your case a 650 or maybe 700 would have been the place to start. you would have a crisper throttle and more off the line than with the 750.
That said.........the Edelbrock is a fine carb for street use.....
It is not and never will be the choice for any kind of competition use.
Sorry Edlebrock lovers but:
If it was such a good carb every muscle car would have had them from the factory......but they did not.....They all had Holleys
 

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well, other than the afb's that some chryslers had......theres a reason holleys are on the vast majority of race cars!!!!

I still find it hilarious vic edelbrock built some example cars that used holleys a couple of years ago
 
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