Edelbrock AVS2

[alsant]

I have a QFT 680 on my Dart now and I’m thinking of replacing it with a Edelbrock AVS2 650. So what you guys think ?

 

[66 Sat]

Cruiser or street/strip? What car, engine etc?

If you just like pottering around then the AVS2 is a great choice (although hard to start after sitting for a few days compared to the Holleys). Easy to tune too.

Mine was underwhelming and is sitting in a box in my shed. Not sure if I got a bad example or not, it felt great in isolation but in back-to-back comparisons with a 600 V/S Holley 1850, and a 650 D/P Holley it felt flat and lifeless.

 

[alsant]

Yes I should have given some more info , it’s a 318 that is .40 over with a 340 cam and 4 spd. 1965 Dart is a fun little car I’m just not happy with the QFT
I’ve change main jets for the altitude up here and also new idle air bleeds. Will change the main jets again , have a bigger power valve I haven’t put in yet don’t know if I will do that just yet.Its not a strip car but it’s nice to take out on the highways out here.

 

[CoronetDarter]

I have the AVS2 on both cars. I really like them; run great OOTB, real easy to tune.

 

[Budnicks]

I'd put a Street Demon 3 bbl 625 (now from Holley)
smaller primaries & large secondary
or the Holley Street Avenger vs 670 4150, style carb
bolt it (either of them) on
right out of the box, no need to tune they are 'near perfect' as is
several I know have done it on a mild combo like yours
(they all had older versions of the Webber/Edelbrocks AVS or AFB knock offs)
before I'd even do the Webber/faux Carter AVS,
unless you find an org. one & rebuild it , for a restoration to look like stock
otherwise get a good carb

I've never had good luck with them Webbers/Edelbrocks, & I'm not a huge fan
& I know how to tune them too, just not to my likings
if the car sitts for periods of time too, will be hard starting
the fuel evaporates out of the bowls in the Webber/Edelbrock, Carter faux carbs
way faster for some reason

to each their own, that's my opinion, honest suggestion
take it or leave it

Engine Masters did a great episode on it too
Cheap Carb Shootout

the Demon will fit a dual plane intake too, notice the underside
they did a test on Engine masters too, great right out of the box
they are a bit harder to tune, have to take the carb off
screws are underneath, but for your combo I'd bet you don't even need to touch it
other than setting the choke for your climate

 

[alsant]

You got me thinking Bud ! Thanks

 

[Geoff 2]

A friend ran the big Demon carb on a 400 engine, bought the tuning kit with it. Was never able to stop the secondary bog. Ph calls to Holley proved useless. Know people who have run the 650 AVS2 on 318's, perform well & no problems.

 

[Geoff 2]

In my opinion, Edel made a fundamental error designing their AVS carb. They added venturiis to the secondaries, which was good. That reqd cut outs in the AV to clear the booster legs. These openings are too big, allowing too much AIR into the engine.....before fuel flows. Result: bog. Carb might work ok on some engines, but other engines with a poorer signal will get a bog.

 

[Photon440]

Isn't that why the AV is adjustable?

 

[Geoff 2]

The AV is adjustable so that once the air speed is high enough, it causes a depression [ vacuum ] that pulls fuel. The reason the AV is adjustable i so that the air speed is high enough so as not to create a bog. The adjustment spring controls the opening rpm, so as not to open at too low an rpm before fuel can flow. Once the AV starts to open, it goes to WOT very quickly. If you watch dyno tests such as Nicks Garage & others, where there is a camera above the carb, you will see this quick opening.
If there is too many gaps around the AV [ which I believe there is on the Edel AVS ], it will reduce the signal & delay fuel flow from the boosters.