AVS2 650 thoughts

[Eric F]

70 Road Runner 383 bored .060 9.3 compression 440 source heads, Mopar 272 cam( 224@ .050 .455 on cam sheet(mopar catalog shows 231@ .050) )
DP4B intake stock high performance manifolds. 2 1/2 exhaust. Current carb Street Demon 750( thermoquad looking one) 1 no mater what I do I can not get the air door adjusted right it’s either too tight and slow secondary opening or opens too quick and bogs. And the spark plugs show at cruise speeds it on the rich side. Outer ring is black. The center porcelain is tan to chocolate color. I bought the jet/rod kit. Guess what the smallest primary jet in the kit is the same one as what that carb comes with. Same with the secondary jet. Same with jet needles. That was a useless waste of money. My daughter was driving behind me and said when I get on it she sees a big puff of black smoke. I’m thinking the goggle valve as Demon calls it.( it’s like a 3 bbl ) is too much for my combination. Not enough air flow to take full advantage of it.
I’m considering an Edelbrock AVS2 650 but unsure .

 

[Orig69]

If the secondary air valve is opening too slowly you can turn the adjuster clockwise until it starts to open too soon and bogs.

Then turn the adjuster counter clockwise a little bit at a time until you get the secondary air valve opening at the right time.

 

[Eric F]

If the secondary air valve is opening too slowly you can turn the adjuster clockwise until it starts to open too soon and bogs.

Then turn the adjuster counter clockwise a little bit at a time until you get the secondary air valve opening at the right time.

I have done exactly what you stated and put that in the post.

 

[Darter6]

Eric,My 2 cents is I'm a big fan of the AFB/AVS style carbs. I had the AVS2 800 on my 472 Hemi.
Ran perfect right out of the box. The 650 AVS2 will be a nice street carb for a 383.
Not too big,not too small.It will have great driveability.

 

[Orig69]

I have done exactly what you stated and put that in the post.

Did you follow the instructions when you installed the carburetor?

Maybe you have a vacuum leak.

 

[Geoff 2]

A friend put a 750 Demon on his 400 engine.....& what a Demon it was.....He bought the tuning kit for it. Numerous ph calls to Holley [ expensive from Australia ] could not fix the bog. Re-fitting the QJ fixed the bog....
You have very sensibly avoided the bigger is better route.

If it was my car, I would use a Carter or Edel 600 AFB. Tried & proven. I like the Edel 650 AVS, but a couple of things I see with it could cause bogging when the secs open. And the bog would not be fixed by tightening the air valve [ AV ].....
This is just my opinion after a close up look at the Edel 650 AVS.
Edel added venturiis to the secondary barrels, where the original Carter AVS had discharge tubes. That was a positive move. However in doing this there is a lot of 'cut out' in the AV to clear the venturiis; so a lot of air able to get it in. Too much air & not enough fuel causes a bog....Also, the original Carter carbs such as the 625 & 750 AFBs that had sec venturiis had an ingenious low speed start up cct...to stop bogging. I could not see anything like that on the Edel AVS.

 

[Jonas Nordstrom]

For your 383 you should have the 625 Street Demon. Better idle, low end and economy.
The AVS2 650 would also be great on your engine with its smaller primary venturis and annular boosters. I say go for it.

Ive tried all of those carbs (AVS2 650, SD 750, SD 625) on my 413........but the winner was a thermoquad.

 

[Eric F]

For your 383 you should have the 625 Street Demon. Better idle, low end and economy.
The AVS2 650 would also be great on your engine with its smaller primary venturis and annular boosters. I say go for it.

Ive tried all of those carbs (AVS2 650, SD 750, SD 625) on my 413........but the winner was a thermoquad.

Thermoquad my 440 motor home loved that carb. So did my 73 power wagon. But I’m trying to my my Road Runner look close to stock. The Edelbrock looks stock enough. I could put a Holley on it as mine was a factory Holley car with California emissions.

 

[Jonas Nordstrom]

Thermoquad my 440 motor home loved that carb. So did my 73 power wagon. But I’m trying to my my Road Runner look close to stock. The Edelbrock looks stock enough. I could put a Holley on it as mine was a factory Holley car with California emissions.

Then I would say: Get the AVS2 650, pop the AVS2 name plate off and send it.

 

[Orig69]

Thermoquad my 440 motor home loved that carb. So did my 73 power wagon. But I’m trying to my my Road Runner look close to stock. The Edelbrock looks stock enough. I could put a Holley on it as mine was a factory Holley car with California emissions.

I have had a few of those original 625 CFM Holley carburetors they work good on a 383 engine and they do have larger secondary barrels.

 

[66 Sat]

If it was my car, I would use a Carter or Edel 600 AFB. Tried & proven. I like the Edel 650 AVS, but a couple of things I see with it could cause bogging when the secs open. And the bog would not be fixed by tightening the air valve [ AV ].....
This is just my opinion after a close up look at the Edel 650 AVS.
Edel added venturiis to the secondary barrels, where the original Carter AVS had discharge tubes. That was a positive move. However in doing this there is a lot of 'cut out' in the AV to clear the venturiis; so a lot of air able to get it in. Too much air & not enough fuel causes a bog....Also, the original Carter carbs such as the 625 & 750 AFBs that had sec venturiis had an ingenious low speed start up cct...to stop bogging. I could not see anything like that on the Edel AVS.

So you've changed your opinion somewhat on the AVS2 Geoff?
There are many threads where you've commented that the AVS2 is the best choice. I bought mine partly based on your opinion.
Only now you've had a close up look and found some things you don't like?
I'm not having a crack at you, just interested.
Mine is back on the car this week after pulling the thing apart completely and going right through it. I have to give it another chance, I've already bought the tuning kit and it's so easy to make adjustments it would be a shame not to try.

 

[Geoff 2]

66 Sat.

I based my original statements on the fact the Edel AVS copied the basic design philosophy of the original Carter AFB/AVS design. Tried & proven, & powered many a muscle car. Plus reports from friends here who have used the 650 AVS & another mate who uses the 800 AVS & drag races it with his Val Charger, runs in the 11s. I actually did some ign tuning on that car, but carb was it situ & really didn't take much notice of it. Plus lots of other positive stories on forums such as this. Also recommended the 650 AVS because I believe 600-ish cfm was a good size for a street driven car, 390-400 ci, moderately heavy
My comments in post #6 was really me thinking out loud....The carb I looked at was on the bench last Wed so I was really able to have a close up look at it. I still think it is great design.
I know you have had bogging problems. If it was my carb I would look to see if there is a way to close up some of the gap around the AV openings for the sec booster legs. The original Carter AVS had a tight fitting AV with small gaps for air leakage. It had one large hole, partly blocked by the choke linkage; Edel added sec venturiis which in my opinion was an improvement. But there is a lot of gaps now because of this & I wonder if this contributes to bogging.

On the sec venturiis in the pic. Is there any hole that are drilled into the circular venturi ring, from the main body where the brass tube is?

 

[66 Sat]

I don't think there's any hole. One thing I did notice is the gaskets were partially covering some of the openings. Not sure what those openings are for but I carefully cut the gaskets to ensure the holes were fully uncovered.

 

[Darter6]

A note about the Edelbrocks. Talked to a rep at the SEMA show and he told me this.
Buy the factory re-mans . The New carbs are made on a assembly line.
The re-mans are gone over by 1 person start to finish.Better quality build.
Since then for the last 20 years I have been buying re-mans and never had any problems.
Extra bonus is they cost less. Just a thought.

 

[Bee1971]

I have voiced my opinion on the Quality Control with Edelbrock on two 800 AVS2 on different threads

However is it a design flaw - casting flaw - or actually quality control or all

The Primary Circuit , idle , off idle , cruise all work awesome from what I have seen or tested
Very easy to tune and control

It’s the Secondary Circuit that I have issues with , Power , Full Throttle

And NO it’s not an air door issue , it’s a fuel flow issue or lack of it

 

[Geoff 2]

66 Sat,
In the pics, I can see a small brass tube next to the 1/4" brass tube. I would poke some wire in it & see where it goes.
I thought you were happy with the Holley 700?

 

[66 Sat]

I was happy with the Holley 700 D/P on the street, but I took it to the track last weekend and it was a disaster. It had zero tuning (my fault), and wouldn't take full throttle off the line, bogging and missing for half the track. After a few runs and trying a few things, with a very gentle start it ran ok for the last 2 runs, best of 14.6 @ 98 but by the time I got home I'd decided to have another go with the AVS. It's just so much easier to tune, using the chart they provide in the tuning kit I bought.
If I was carb expert and timeslips were my only concern then I would stick with the Holley and learn how to tune it but if that was the case I wouldn't be driving a poly with a 3.23 rear and stock converter in the first place.

 

[Houle #382]

70 Road Runner 383 bored .060 9.3 compression 440 source heads, Mopar 272 cam( 224@ .050 .455 on cam sheet(mopar catalog shows 231@ .050) )
DP4B intake stock high performance manifolds. 2 1/2 exhaust. Current carb Street Demon 750( thermoquad looking one) 1 no mater what I do I can not get the air door adjusted right it’s either too tight and slow secondary opening or opens too quick and bogs. And the spark plugs show at cruise speeds it on the rich side. Outer ring is black. The center porcelain is tan to chocolate color. I bought the jet/rod kit. Guess what the smallest primary jet in the kit is the same one as what that carb comes with. Same with the secondary jet. Same with jet needles. That was a useless waste of money. My daughter was driving behind me and said when I get on it she sees a big puff of black smoke. I’m thinking the goggle valve as Demon calls it.( it’s like a 3 bbl ) is too much for my combination. Not enough air flow to take full advantage of it.
I’m considering an Edelbrock AVS2 650 but unsure .

I have a mild built 440, .030 over, 440 source heads, competition components hydraulic roller cam .600 lift intake .584 exhaust [email protected] 235 intake 250 exhaust, Edelbrock performer RPM intake, Edelbrock AVS 2 650 carb and stock HP manifolds. I have friends that kept telling me the 650 wouldn't be enough carb for my build until I outran every one of them. This AVS2 is a perfect street carb, the light-to-light Excelleration is incredible. The only thing I did to the AVS 2 was I changed the springs from the factory reds to the pink springs and changed the secondary jets to .104's from the factory .098's. It's a 4 speed car and she pulls very hard. I even bought the AVS 2 800 to try out and it just didn't perform as well as the AVS 2 650 on the street. You definitely will not be disappointed with the AVS 2 650

 

[Geoff 2]

Last week I removed an Edel 800 AVS from a 360 that was powering a 3900 lb Dodge. Edel hadn't been dialled in properly at idle, & I felt it was too big for this cu. in/car weight.

Fitted a 625 Carter AFB & acceleration was MUCH better. Bigger isn't always better....

 

[Bee1971]

With the Annular Boosters on the AVS2

Take away about 50 cfm on the flow bench from the huge boosters alone

Then add the tower and choke

I would Bee surprised if an 800 AVS2 could even flow 650-700 cfm STOCK

So where does that put the 650 AVS2 - 550-575 cfm STOCK or less


Some Chevy guys where talking this very subject at the Track Friday Night after some flow bench testing versus the Edelbrock Thunder Series AVS 800 and AFB 800