what CFM

generaljmwlee

generaljmwlee

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what cfm carb did the 69 roadrunner with the 383 HP motorcome with?
what carb would you recomend Holley or the Edelbrock
by the way its a stock build with mild cam
 
A Carter AVS is what your car came with. IIRC it is a 625 CFM. That will be good for a stock engine.
 
What rear gears and tranny do you have, and headers or intake? Any idea of what cam?
 
it it 383 4spd 355 rear
just was looking for a carb online at edelbrock.com and it seems that they only have a 500,600,750,800,cfm if the 750 would be too much would the 600 be too small?
 
An Edelbrock Thunder AVS 650 would be perfect for the car as would a 670 Holley Street Avenger with vacuum secondaries. With a stock engine (heads, cam, valves) you can only get so much air/fuel through the engine (max cfm is fairly low), therefore air flow velocity becomes more important to your situation. A smaller cfm carb will help keep velocity high and therefore help throttle response.
An article I read years ago mentioned that the factory rating on the 383 AVS was in the 600+/- cfm range but in actuality it flowed more like 450 cfm. The 440 AVS was rated higher but actually flowed around 650 cfm according to the article.
The popular fix to get the 383 running better was to swap to a 440 AVS as the additional air flow helped out.
If I had a stock engine with your gears I'd go for the smaller Thunder AVS carb since I have a soft spot for the AVS carbs. If Holley is your bag then go for the 670 cfm Street Avenger with vacuum secondaries. Either one will give great throttle response and decent fuel economy.

Holley Street Avenger 670 cfm w/vac. sec., elec. choke & secondary quick change kit factory installed $349.99
http://www.jegs.com/p/Holley/Holley-Str ... 9/10002/-1
Additional secondary springs for fine tuning $11.99
http://www.jegs.com/i/Holley/510/20-13/10002/-1

Edelbrock Thunder AVS 650 cfm w/elec. choke $359.99
http://www.jegs.com/i/Edelbrock/350/180 ... tId=752435
 
I don't have the knowlage you guys have. I ran an AVS on the 440 in my Charger and in Freebird. Never cared much for the few Holly's I did have. This car has a Holley on it. It's OK...but the new Edelbrock/AVS my Uncle put on my truck impresses me way more. Maybe after the daughter finishes Ohio State this year...and the Wife's car is paid off next year, I'll get a new AVS for the bird. My 383 was supposed to have only 3500 miles on it when the PO I got it from bought it. And the guy he got it from was supposed to have done some racing with it. I'm kinda guessing when that guy sold it he must have done some parts swaping, so it just might not have the right set up now. Definatly needs some 3.55s or even 3.91s to wake the 383 up some.
 
droptop said:
A Carter AVS is what your car came with. IIRC it is a 625 CFM. That will be good for a stock engine.
Click to expand...

Droptop is right on.

A 750 runs very well on a stock 383. I have run one for years now. A 750 Double Pumper is what I have a will roaly kick ass over a AVS. :cents:
 
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