Mopar4Speed
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Is the Avs II eddy as good as everyone is raving about or is it all just hype?
340 Advice
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rumblefish360
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Here’s your electric choke! 2-800 TQ’s!
Challenger340
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Yep.... either works really well
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As I previously mentioned, the Edelbrock AVS 2 (or AVS II, if you prefer), is a hermaphrodite, or a combination of the old Carter AFBs, that used counterweighted velocity operated air valves above the secondary butterfly valves but were below the secondary booster venturi. The "new" AVS 2, removed the velocity operated air valves and added the "old" Carter AVS air valve blade, but maintains the secondary booster venturi below the air valve blade. Notice the clearance slots in the back edge of the AVS 2 air valve blade...that allows the air valve blade to clear the booster venturii fuel delivery tubes when it opens.
True...the PRIMARY BOOSTER VENTURI's annular feature is a great improvement over the origional Carter design. This feature allows for better atomization of the fuel, resulting in more even fuel distribution and significantly better off idle transition to the main fuel. But with modifications to the origional Carter design's off idle/transition circuit similar results can be achieved....IMO.
One additional factor to consider, for the Carter TQ proponents, consider the Holley Spread Bore design. It uses the time honored Holley designs, BUT the 4165 model never achieved great popularity as a Quadrajet replacement.
To answer your origional question, re popularly of the AVS 2, you'll only hear about the good aspects but seldom or never the bad results .... its only human nature to suppress our failures or mistakes.
BOB RENTON
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Sparky Anderson
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I run a holley 3310 750 vacuum secondary on my 340 with 4:30 gears and gets out of the hole real strong and surprises a lot of big block cars.
JC Boatguy
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Now I gotta jump in. I owned a 340 with 284 duration cam 445 lift and ran a 650 Holley spread bore double pumper mechanical secondary and that carburetor was unbelievably efficient and had absolutely instant off the line throttle response and top-end. It had a 10cc secondary accelerator pump chamber which made absolutely Wicked throttle response, also a 4 speed car.
72sunroof
Well-Known Member
This 1000%. I have a similar build and l run a 850 Thermoquad with 100 primaries and 147 secondaries. It pulls to 6500 rpm.
They sell an aftermarket electric choke for thermoquads. Or Get the biggest Street Demon 750 i believe.
rumblefish360
Well-Known Member
Really? I’d like to see that. Link please.
72sunroof
Well-Known Member
https://www.carburetor-parts.com/cu1245.html
I use the Mopar time delay module hooked up to the choke with heater wire.
rumblefish360
Well-Known Member
Wow! I have fiddled with my own version a long ways back by bending up my own tin bracket and making use of an Edelbrock choke. This is much nicer. I had no idea this was available at all. Glad your here & thanks for that link!
JC Boatguy
Well-Known Member
Bobs right! Holley spreadbore is EXCELLENT!!! MY 340 had one and it really is the best of both worlds, great economy and gobs of power when needed, absolute INSTANT throttle response.
rumblefish360
Well-Known Member
Anyone use the 4011 spreadbore Holley?
I know this is an old thread, but I built a stroker 340 with 416 cubic inches. I put an 850 Carter Thermoquad from a 400 on it.
I know the Thermoquad is often an afterthought to other carburetors, and it was in my mind too. ...UNTIL I put one on my 416 stoker motor.
A Thermoquad really is a great carburetor. First of all, the small primary bores give you great throttle response as well as optimal fuel economy. But then the massive secondaries give you the power when you put your foot in it. In addition to that, the secondaries only open based on demand from the car, so you really can't over carburate your car, unlike for example, a traditional Holley.
I know the Thermoquad is often an afterthought to other carburetors, and it was in my mind too. ...UNTIL I put one on my 416 stoker motor.
A Thermoquad really is a great carburetor. First of all, the small primary bores give you great throttle response as well as optimal fuel economy. But then the massive secondaries give you the power when you put your foot in it. In addition to that, the secondaries only open based on demand from the car, so you really can't over carburate your car, unlike for example, a traditional Holley.
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6PKRTSE
Well-Known Member
I have run both 650 and 750 carbs on my 340 engines as well as 1407 Eddy carbs depending what was done to them with no issue with either.
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