Okay I know this topic has probably been discussed to death, but here's my experience with the 2. I put a 670 street avenger on my 350 and it did not like it. It was a brand new build and brand new carb

355
10:3.1 advertised compression pistions
Nodular crank
#5 heads with SS valves, HP springs and roller tip rockers
Edelbrock performer RPM cam, lifters and intake
Mallory unilite with MSD wires and autolite 85's
Flowtech ceramic coated headers
RobbMC fuel pump
TH350 with 2500 stall
3:42 gears

With the 670 it stumbled from idle, ran rich and overall did not perform well. Out of the box with nothing changed. Now I admit I am no Holley master so I probably did not tune it right. I tried different pump cams, adjusted accelerator pump, tried various discharge nozzles and jets with not resolve. I read all the articles and tried all the tricks with no success

I decided to put on a new 650 Edelbrock AVS and out of the box it works great. No stumble, idle is better, running cooler and not rich.

Could it be that the AVS is closer in design to the Q-jet which I hear is a great carb for a SBO?

Thanks

 

My experience exactly. Edelbrock is the best carb I've ever used.

 

I've heard Holleys are better.

Now I'm confused

 

Well, they are definitely better than no carb at all...

 

You'll find as many opinions on this subject as you would on any political issue. I prefer Holly carbs. I have run then on everything I own for over 40 years. I find them easy to tune and very responsive. I will admit they do not get the gas mileage of other carbs (according to people I know when we have done comparisons) but then again I don't build my engines for mileage. What ever floats you boat I say

 

Never had any luck with Edelbrocks, had 3 over the years, sent them all back or sold them. Jmo.

There's something wrong with your Holley. I did a 436 BBC last year with an out of box 770 Avenger. Worked perfectly, didn't have to touch it. Did a 362 SBO with a 670, same thing, ran great untouched.

 

best carb i have had was a 650 double pumper with mechanical secondaries but i have had and find the performer edelbrock easy to dial in my q jet is still too new to praise yet.

 

First I tried the edelbrock 750 performer. Okay, but the engine seemed to want more.
Next, I put on the 870 holley street avenger. Ran like hell, but I could not tune the rich idle out of it.
Now, I have a custom built 800 cfm quadrajet off a 403 built by Mountain Man carbs to my engine, convertor, trans, and rear end gears. Runs perfect. No rich idle, and actually goes better than the holley. JMO

 

 

Power valve checked out right. There is alot of the same rich idle posts with these on other boards with no real answer. Well at least a year ago. Anyways, I have had the quadrajet on for about a year now and still am very happy with it.

 

Edelbrock is better for street. Holley is better for drag.