Street Demon or Edelbrock AVS2 or ?

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Not sure what 'way out of it's comfort zone' means [ Post #48 ]. Or that the secondary AV spring is 'pretty fragile'.
If this 800 cfm carb is out of it's comfort zone, it might be too big for the engine & a 625 cfm version might have been better.
Lean spot on sec opening can be a few things: float level, jets too small, spring too loose. And that is just the carb, not talking about ign etc....
 
Siren,
If Holleys are so good, why is every man & his dog making 'better ones'......
They are a crude design & the power valve arrangement approaches joke status....
 
If you haven't tried a Holley since the 70's your opinion is not valid of anything built in the last 10-15 years.
Sure, right. Invalid opinion. So what changed in the last 10 years? I still will not touch one. Keep tuning, rebuilding, and driving your Holley on the street. My friends have learned, and they both race. Neither has a Holley on their street cars anymore. As a matter of fact, one called me up to say how great the AVS 2 worked on his street rod after he got tired of dorking with the Holley. The other pulled all his stupid Holleys when his brothers beautiful 55 Chevy almost burned to the ground. Keep believing the "race" marketing and buying all your tuning parts.
 
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Sure, right. Invalid opinion. So what changed in the last 10 years? I still will not touch one. Keep tuning, rebuilding, and driving your Holley on the street. My friends have learned, and they both race. Neither has a Holley on their street cars anymore. As a matter of fact, one called me up to say how great the AVS 2 worked on his street rod after he got tired of dorking with the Holley. The other pulled all his stupid Holleys when his brothers beautiful 55 Chevy almost burned to the ground. Keep believing the "race" marketing and buying all your tuning parts.

I want to try one of those new Edelbrock 4150 carbs, looks like they took everything wrong with a traditional Holley and fixed it. Seems like a similar deal with the Summit carbs.

If I'm not mistaken Holley is actually stopping production or at least any further R&D of carburetors and putting all of their focus into EFI systems.
 
I want to try one of those new Edelbrock 4150 carbs, looks like they took everything wrong with a traditional Holley and fixed it. Seems like a similar deal with the Summit carbs.

If I'm not mistaken Holley is actually stopping production or at least any further R&D of carburetors and putting all of their focus into EFI systems.

I was like that, always wanting to try and compare everything. Nothing wrong with that at all. Since I personally do not race, I have my favorite combinations that have proved themselves over time. What ever works for you.
 
Not sure what 'way out of it's comfort zone' means [ Post #48 ]. Or that the secondary AV spring is 'pretty fragile'.
If this 800 cfm carb is out of it's comfort zone, it might be too big for the engine & a 625 cfm version might have been better.
Lean spot on sec opening can be a few things: float level, jets too small, spring too loose. And that is just the carb, not talking about ign etc....
Well, to start I’m flowing almost as much fuel through it as it can physically flow. I have run it without rear jets and it is just slightly fat. I have had to open up the accelerator pump nozzle to help with the lean spike at the hit. The air door spring is fragile because if you tighten it more than 1– 1 1/2 turns it breaks and the part is not available separately. With full spring tension I’m still slamming the air door open so fast it spikes lean. I have fitted an air horn for it that is good for 5-10 hp, but can’t use it because it makes the air door open even quicker. I have timed how fast the door opens. About 1/10 sec from start to full open. I’m required to run an AVS, but that is why mine is way out of it’s comfort zone. I have thought of running Q16, but I don’t think the 800 can physically flow 25% more fuel than what I’m currently running.
 
Q16? Is that a type of fuel. Sure you can flow more fuel. Not sure what you mean by cannot flow 25% more fuel. For reasons known only by Edel these large carbs [ 800 cfm ] come with small 0.093" n/seats. In contrast, the smaller Carter 625 cfm Comp Series came with 0.101" n/seats & there are two larger sizes available, 111 & 120. Increasing jet size is self explanatory. Get bigger jets or drill them to a larger size.
 
Just to be clear, the AVS has the spring loaded air door. The “afb” version has the counter weights. Both of the Eddy’s use the AFB base with the slots for counter weight shaft. I run a 800 AVS, and it is WAY out of its comfort zone, but still working. It really needs a secondary transition system like the carter AFB. The small port that the counter weighted butterflies pass by. Add that the AVS spring is pretty fragile…..and you get lean spot on secondary opening. Also the secondary emulsion tube necks down at the bottom. Again, mine is way out of its comfort zone.
What cubes are you running the 800 on? If the secondary emulsion tube is pinched at the very end then that is the limiting factor in fuel flow on the secondary's not the jet size if it is bigger. Can you post a pic of the secondary booster emulsion tube?

You can also make your own springs if you really need a stronger one.

Making Springs At Home
 
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Post #60. I have heard of this, but yet to see one & I believe it was only the 750 AFBs that might have had this. Maybe a production error, later fixed?
 
I have heard of this, but yet to see one
1682759749822.jpeg

You have now.....
 
Siren,
If Holleys are so good, why is every man & his dog making 'better ones'......
They are a crude design & the power valve arrangement approaches joke status....

Really go to the track some time and see what people who race seriously are running.. Holley like carbs. have drastically improved over the years,my last 2 carbs. were Quickfuels 850 "BEST" carb I ever used,then again I know how to tune which I did when needed for weather conditions..
 
Really go to the track some time and see what people who race seriously are running.. Holley like carbs. have drastically improved over the years,my last 2 carbs. were Quickfuels 850 "BEST" carb I ever used,then again I know how to tune which I did when needed for weather conditions..

So how do "Stock" and "Super Stock" cars go so very fast with those "lesser" carbs? I guess they are not serious racers. No thank you Holley.
 
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So how do "Stock" and "Super Stock" cars go so fast with those "lesser" carbs go so very fast? No thank you Holley.

You might want to go to the track and look under the hood of those cars you'll find Holley carbs especially the S.S. cars!!!..besides those cars are so modified it doesn't make a difference what they run for a carb. but they run better with a Holley carb. then that Edelbroke junk!!!
 
You might want to go to the track and look under the hood of those cars you'll find Holley carbs especially the S.S. cars!!!..besides those cars are so modified it doesn't make a difference what they run for a carb. but they run better with a Holley carb. then that Edelbroke junk!!!
You have no clue. Super Stock and Stock class cars must run OEM carbs. One of my friends raced Super Stock. 10 seconds flat with a low compression Chevy 350 and a Quadra-Jet. His friend raced a Stock class 71 340 Duster. He was so fast, Chrysler was giving him parts to try. Raced using a Thermo-quad. After hanging around those guys I figured who was BSing me. Never looked back. Sold all my Holleys and the pile of "tuning" parts. Wow, better running cars, better mpg, and set and forget. Stopped having to "tune my stupid Junk Holley and rebuild it all the time. Now I just enjoy my car. Believe what you want, just don't try to sell it to me. I've seen the light! I've also loaned carbs to friends who thought Holley was "THE" carb, and none of them wanted give my carb back.
 
The Eddys are an AFB style. The street Demon is a Thermoquad style. The difference is the secondary air door. The air door on the Eddy AFB is under the boosters. The air door on the Thermoquad and Street Demon is above the boosters. That's a huge difference. The Street Demon was designed right off the Thermoquad. They even look very similar.
Good morning Rusty, the OP was asking about the AVS2 series. On these, the air door is also above the boosters.
 
Just to be clear, the AVS has the spring loaded air door. The “afb” version has the counter weights. Both of the Eddy’s use the AFB base with the slots for counter weight shaft. I run a 800 AVS, and it is WAY out of its comfort zone, but still working. It really needs a secondary transition system like the carter AFB. The small port that the counter weighted butterflies pass by. Add that the AVS spring is pretty fragile…..and you get lean spot on secondary opening. Also the secondary emulsion tube necks down at the bottom. Again, mine is way out of its comfort zone.
What do you mean when you say the carb is "way out of its comfort zone"? Thanks.
 
Good morning Rusty, the OP was asking about the AVS2 series. On these, the air door is also above the boosters.
I know, but my comment was in response to someone else who brought up the AFB style. Plus, it was in August of 2020. Are you looking to argue that badly? You won't get one here.
 
I know, but my comment was in response to someone else who brought up the AFB style. Plus, it was in August of 2020. Are you looking to argue that badly? You won't get one here.
My apologies, not looking for an argument at all, sorry you took it that way, it wasnt my intent. I read this first thing this morning, before my coffee, I didn't notice the date.
 
My apologies, not looking for an argument at all, sorry you took it that way, it wasnt my intent. I read this first thing this morning, before my coffee, I didn't notice the date.
No biggie. I do it all the time. I was just wonderin.
 
My secondary emulsion tube did not neck down, kinda weird, some do some don’t. it’s wide open. I have restricted the bleeds to try and pull more fuel quicker through the sec boosters. I’m running the largest needle and seat available. Jets only come so big because the passage through the carb is only so big. I have run it without secondary jets in the carb, it was only slightly fat. Q16 is an oxygenated fuel. If your combination is air flow restricted, you can run oxygenated fuel to get more oxygen into the cylinder, however you need to run about 25% more raw fuel. Which at this moment in time I can’t do, without drilling the fuel passages bigger. I’m 410 CI, shifting at 6500 rpm crossing at 6800. The 800 eddy is not really a “race” carburetor.
 
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