AVS2 compared to Street Demon?

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gzig5

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Has anyone done a comparison of the 625 Street Demon to the "new" AVS2 650? Both seem to get good reviews as a street carb that works well out of the box with good throttle response. I need a new carb for my 340 and one of these would carry me over pretty well as I prepare for a proper full tilt build. I'm leaning towards the SD but the annular booster on the AVS2 is intriguing as well. I'll probably need a 750 or more when I'm done, but at this point the smaller carb should hang in there until the very upper rev region.
 
I hear a lot of good things about the AVS, I am thinking it’s Rusty who is probably the man to talk to about these, he knows the edelbrock stuff really well.
 
I haven't had any time with the new AVS yet. We sell them at work. Looks nice. What I have done is swap an Edelbrock 625 AFB for a 625 Street Demon. I found the SD on Ebay needing some small repairs and a kit cheap so I got it. So far, it's been a pretty big improvement over the Edelbrock.......not that the Edelbrock was a poor runner. Just the contrary. With the SD though, the idle is smoother, the mileage picked up, but where it really shines is the transition into the secondary barrel. It's very smooth yet very noticeable at the same time. It goes right into the secondary circuit smoothly, but you dang well know when that thing opens. It sounds good too. lol
 
I agree with Rusty, It's a apples to apples comparison.They are both good,so good you wouldn't go wrong with either.
 
I agree with Rusty, It's a apples to apples comparison.They are both good,so good you wouldn't go wrong with either.

That's what I was afraid of. I guess it's not a bad thing though.
I've convinced myself that until I go to aftermarket heads, the 625/650 size will suffice. I don't want to risk the off-idle and part throttle response by going too big at this point. Not having to mess with a bunch of tuning is appealing too.
 
I've got the electric choke AVS2 on my 70 dart 340, 4 speed. Best carb I've ever owned. Starts great, throttle response is incredible. I highly recommend it!
 
Unless there is an identifiable difference in fine tuning capability or price, I guess I'm going to have to polish up my fifty cent piece and give it a flip.
 
Has anyone done a comparison of the 625 Street Demon to the "new" AVS2 650? Both seem to get good reviews as a street carb that works well out of the box with good throttle response. I need a new carb for my 340 and one of these would carry me over pretty well as I prepare for a proper full tilt build. I'm leaning towards the SD but the annular booster on the AVS2 is intriguing as well. I'll probably need a 750 or more when I'm done, but at this point the smaller carb should hang in there until the very upper rev region.
I have had two Demon carbs, both were junk, one stuck the throttle shaft.
I know for awhile Summit would not sell them, to many returned.
I have a Edelbrock on my 340, smooth sailing for the last 2 years.
 
Used a avs2 650 on a 340. Ran perfectly out of the box. I would recommend it for a street car
 
I read many reviews about the AVS2, I was convinced and had to go buy one. I did, at the end of December. I haven't installed it as yet. The thing that drove my decision is the off-idle stumble that I have with the 1405 Edelbrock. My Scamp / LA 360 is as bad with the stumble as I ever read about. But other characteristics of the Edelbrock I really love. The serviceability for tuning. And because I run an AFR gauge, I have tuned the 1405 very very well. I've been inside that thing dozens of times changing every nook and cranny to optimize the tune. It's very easy (but I serious dislike the microscopic pump and choke link clips). But yet after all the tuning, I still have that off-idle stumble.

So what I read about was that the annular boosters eliminate that. We shall see. That and the secondaries are vacuum actuated compared to the mechanicals of the 1405. I get a big lean gulp of air (and not quite a stumble, but a power drop) when I floor the 1405 and I get that lean gulp. I read that the big lean gulp is also avoided with the vacuum secondaries. And lastly, in the dyno tests, the low and mid range power was much improved with the AVS2 due to the annular booster atomization. Top end power on the dyno test I saw was just a few hp more for the AVS2. But virtually the same top end power. Meaning, the AVS2 would be much better on the street. And that's where 95% of the time my Scamp will be.

Go Mango's post backs up what I read about throttle response (no off-idle stumble). I've read that the AVS2 feels a lot like fuel injection. I hope I remember to come back in here and update once I install my AVS2. I got mine barely over $300. I bought the manual choke though (1905?).


7milesout
 
Hey, thanks for that write up! I am going to be using an 85 360 truck Quadra-Jet, chokeless with a milled airhorn, someday. I’ll have to double check but it has something a lot like an annular primary booster. Still just got the two big fuel dump tubes in the rear. It’s a warm weather only driver, so a choke isn’t too big of an issue. A little extra air door spring tension to prevent “Quadra Bog”. I’ll have gear in first, at least 3.90, maybe deeper. If I don’t like the way it works out, I’ll go with a new AVS, one of the 650 cfm.
 
One other question, are the flow rates on the AVS as “hopefully optimistic” as on the performer series carbs?
 
The secondary's booster on the performer and AVS2 is called a downleg booster as I recall. Heck, the primary booster on the Performer is also a downleg booster. And it has another name it is referred to sometimes, but I don't recall it off-hand.

And by flow rates, I'm assuming you mean airflow rates. I suspect there is very little to no difference in the structure of an AVS2 650 CFM, and a Performer 600 CFM primary and secondary bores. My guess (and I don't know this, and only speculate) is that the 50 CFM difference is based on the airflow rate through the annular boosters versus the downleg boosters.

If I'm right about that, the maximum useable airflow would be ~50 CFM more. However, I'm not familiar with what you might be inferring with the "hopefully optimistic." It might mean something I'm not following. Otherwise, to answer your question: Yes.


7milesout
 
Go Mango's post backs up what I read about throttle response (no off-idle stumble). I've read that the AVS2 feels a lot like fuel injection. I hope I remember to come back in here and update once I install my AVS2. I got mine barely over $300. I bought the manual choke though (1905?).

Get-er done! Looking forward to your report.
I can't get my car out of storage until mid-late April so I've still got a couple months to ponder the question.

One thing I have heard is that the Street Demon won't accept a drop base air cleaner because of interference with the choke mechanism. Does the AVS2 suffer from that or will it take a standard drop base?
 
Get-er done! Looking forward to your report.
I can't get my car out of storage until mid-late April so I've still got a couple months to ponder the question.

One thing I have heard is that the Street Demon won't accept a drop base air cleaner because of interference with the choke mechanism. Does the AVS2 suffer from that or will it take a standard drop base?
this is the stock 1970, 340 air cleaner with a drop base. It fits fine.
15489727735261185377101607119914.jpg
 
Autozone has a 20% off thing going on now and both the AVS2 and Street Demon are available. Unfortunately, they don't carry the SD 1901 with the polymer body but do have the 1900. AVS2 is a few bucks more. Decisions, decisions.
 
Autozone has a 20% off thing going on now and both the AVS2 and Street Demon are available. Unfortunately, they don't carry the SD 1901 with the polymer body but do have the 1900. AVS2 is a few bucks more. Decisions, decisions.
AVS2.
 
Craptacular. The Autozone 20% and O'Reilly 25% are not valid on Edelbrock carbs and some other performance brands. Summit has 10% now.
 
Craptacular. The Autozone 20% and O'Reilly 25% are not valid on Edelbrock carbs and some other performance brands. Summit has 10% now.

O'Reilly can match Summit all day long on carburetor prices. I do it all the time.
 
O'Reilly can match Summit all day long on carburetor prices. I do it all the time.

They all have essentially the same $355 price for the 1906 electric choke carb. Even if they match it, Summit still has free shipping which they may not match. $30 is not the end of the world and I did find out that Edelbrock has a $50 rebate bounty program if you send back an eligible carb after buying an AVS2. That will get the net price to less than $300 which i can deal with.
I wish they took Cabela's points...
 
Get-er done! Looking forward to your report.
I can't get my car out of storage until mid-late April so I've still got a couple months to ponder the question.

One thing I have heard is that the Street Demon won't accept a drop base air cleaner because of interference with the choke mechanism. Does the AVS2 suffer from that or will it take a standard drop base?
AVS2 I have needed about 3/8" spacer between the drop base aircleaner base and the carb. The fuel line inlet was hitting the aircleaner. No problem with the choke.
 
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They all have essentially the same $355 price for the 1906 electric choke carb. Even if they match it, Summit still has free shipping which they may not match. $30 is not the end of the world and I did find out that Edelbrock has a $50 rebate bounty program if you send back an eligible carb after buying an AVS2. That will get the net price to less than $300 which i can deal with.
I wish they took Cabela's points...

You don't pay shipping at all through O'Reilly on parts that are not special order. O'Reilly will match regular prices from Summit. Not sale prices. I can go down to about 319 from the marked 336 price. Not every store will do that. A lot of times I look for the cheapest price. If it's close, I prefer to buy locally to support my local tax base and if I ever have an issue, I can deal fact to face, instead of over the phone or internet.
 
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