Holley Street Avenger 770 for 408?

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dust

dust

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I have a 408ci running well with the Mighty Demon 650 but want electric choke. I don't like tuning carburetors, I'm at the point where I just want to drive it and not sit with my foot on the pedal for 10+ minutes to warm it up.

I've heard negative about Street Avengers in the past. What are thier drawbacks?

Duster, Edelbrock heads, 4 speed, 3.23 rear.
 
Also, is the electric choke unit independent from the engine?
 
The electric choke is attached to the side of the carb. First things first, drop that demon in the trash. Any carb you do get will have to be tuned to that engine. Try either the holley or an Eddy 750.
 
Go with an 870 Avenger. It's what I spec on street 4" arm engines. VS, electric choke. Bolt on, jet, maybe power valve depending, and go.
 
moper said:
Go with an 870 Avenger. It's what I spec on street 4" arm engines. VS, electric choke. Bolt on, jet, maybe power valve depending, and go.
Click to expand...

Why 870 over 770?
 
I've ran a couple of Street avengers and both worked fine after I tuned them for the engine. You won't buy any carb and take it right out of the box and slap it on and it be calibrated perfect unless you get super lucky or buy a purpose built carb from a good carb builder that's specifically calibrated for your car. The choke is completely independent from the engine. All you do is hook up a B+ wire from the ignition switch and it does all the work. But the chokes on the carbs I had needed quite a bit of tweaking to make them work good.
 
Because the engine will make good use of it. The air bleeds and factory set orifice sizes suit it well. It has big enough primaries that it works well and has great throttle response. Part throttle cruise manners are excellent. It will make more power with no loss of drivability with it. Strokers love big carbs.
 
I have a 870 Avenger right out of the box on my 360. I have nothing but good things to say about it... I fought 4 different carbs on that motor... this one just landed perfect. I dunno... unless I am just lucky.... that is the best Carb I have owned.

-RPM
 
RPM said:
I have a 870 Avenger right out of the box on my 360. I have nothing but good things to say about it... I fought 4 different carbs on that motor... this one just landed perfect. I dunno... unless I am just lucky.... that is the best Carb I have owned.

-RPM
Click to expand...

That's interesting to hear, looking at the numbers and the Holley cfm to cu.in. chart; I'd think that 870 would be too much carb for even a (mild) 408. How is throttle response on your 360 and how did you decide on the 870 over the 770?
 
I've got a street Avenger 670 carburetor. I haven't rejetted it since I took it out of the box. The only adjustments I've made are to the idle screws based on readings from a vacuum gauge.

I originally bought this for a 302 Ford in a 66 fairlane. Worked great. Great driveability.

Put it on the stock 318 in my Dart (when I installed an LD4B). Also worked great. Great driveability, the manifold and carb really helped out the 318.

Put it on my cammed up 5.9 and reset the idle mixture. Works great. I intend to tune it more thoroughly on this car, but it almost drives like an injected car right now.

With the electric chokes you have to remember not to leave the key on without the engine running for long periods of time. The choke relies on the engine drawing air through the choke to cool the spring.

I've found that the choke requires adjusting based on what time of year it is. For the summer months, I just set it to come off as quickly as possible and that's always worked for me.

Steve
 
dust said:
That's interesting to hear, looking at the numbers and the Holley cfm to cu.in. chart; I'd think that 870 would be too much carb for even a (mild) 408. How is throttle response on your 360 and how did you decide on the 870 over the 770?
Click to expand...


I have never seen anyone really go by that chart... they always went bigger on the carb. I never have went with they advise. The stock Thermoquad that most mopars engines came with was 850 cfm if Im not mistaken.

I would listen to moper anyways! :toothy10:
 
mullinax95 said:
I have never seen anyone really go by that chart... they always went bigger on the carb. I never have went with they advise. The stock Thermoquad that most mopars engines came with was 850 cfm if Im not mistaken.

I would listen to moper anyways! :toothy10:
Click to expand...

I agree, that chart always seemed to undercarb what engine combo you are asking about. I have always used the formula of about 1.75-2 times the cubic inch, yet it all depends on cam, compression, stroke, heads, etc.
 
The holley cfm/cubic/rpm chart is just a guide line.

My 340 runs better/faster with a 750 than 650 with next to no sacrifice of low end.

I like the the holley 830 annular for 408-416 strokers, street/strip 440's, and built street 383/400's, I know thats broad but I'm talking about driving them on the street.
Once you get 11.1, w2's & solid roller on a sb stroker then it's more like 850-950cfm, same for 383. On the 400-440 it's when get past 11.1+comp, 300+cfm heads and over 7000 rpm=950-1050cfm

But 1 or 2 key things could offset that general guide line I just set.
 
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