Edelbrock Carb for 383... 600 or 750 cfm?

[Fleet 500]

What size Edelbrock carb (cfm) do you guys suggest for my '66 Plymouth Fury VIP with 383-4 bbl? Engine is stock except for electronic ignition upgrade. Rear axle ratio is 3.23:1. 14" tires. 3-speed Torqueflite with shift kit.
10.0:1 compression ratio, max hp 325 @ 4800 rpm.

Is a 600 cfm big enough? I don't expect my max. engine revs to exceed the revs at maximum horsepower (4800 rpm). Using the well-known formula (cu. in. x max. rpm divided by 3456) I get 532 cfm.

[GoodysGotaCuda]

In my opinion, the calculated figures work great on the table. But real world seems to vary for sure. Depending on location, size of the vehicle, rpm range, etc. The smaller carb would likely give you better low end/throttle response. Which at max of 4800rpm, I'm assuming you are looking for. I have a 650cfm Thunder AVS carb that has been very good to me and my 318. I've done a few tweaks on it to make it perform better with my previous high stall converter, has done me right. I would certainly buy another, and I would certainly NOT buy a 'performer' series carb. Compared to the AVS. Secondary adjusting is so easy on the AVS, have fun on a performer/afb carb. 

[Fleet 500]

Yes, I have heard that those AVS carbs are easy to make adjustments. And, yes, that formula does not taken into consideration other factors like the ones you mentioned.

Fortunately, there is no rush for me to buy a carb... I can take my time. My engine has the original Carter AFB carb, model #4131.

[Chryco Psycho]

I would use the 750 AVS

[Fleet 500]

I would use the 750 AVS

Isn't 750 kind of big for a stock 383? It does have the stock cam and exhaust.

[GoodysGotaCuda]

Isn't 750 kind of big for a stock 383? It does have the stock cam and exhaust.

I would agree on saying a 650 would probably be better suited due to it's going to be used to cruise with/lower rpm. If that 383 was going for power and high rpm it would run out of steam. I'd think it would do just fine and have very nice throttle response/drivability.

[Fleet 500]

I would agree on saying a 650 would probably be better suited due to it's going to be used to cruise with/lower rpm. If that 383 was going for power and high rpm it would run out of steam. I'd think it would do just fine and have very nice throttle response/drivability.

I think so, too. A 650 should be just about right.

[Chryco Psycho]

I have always used 2x the CI as a base line even on a stock engine , the 750 is the right size

[moparmike70]

I had a 700cfm on my stock 383 and it worked fine. I have a slightly modified 650 on my 383 now and no problems with it. My engine has the 484 mopar cam in it and is not stock. Unless you have port work and are able  to use the higher revs there really is no use for a larger carb.

[dodge freak 2]

That is the thought of many but I seen on speedtalk were many pro racers are on saying a larger carb--set up right--makes more power not only at higher rpms but at lower rpms too.

Now I have had bad luck with the Eddel 800 and I seen others saying the same thing.

Holley carbs are a totally different breed. Seems like those carbs keep making more power the larger you go. Booster design might have some thing to do with it

[moper]

I think there are people who would have trouble with God supplying carbs, and then there's guys that can make a V8 run well with 4 drinking straws and some duct tape. Mind what you read, and try to research the "whys" behind the performance. Speedtalk "Advanced engine" section is very good for this. In terms of your car, I would go 750. Because that's what I've foiund works very well all around. Holleys are no different than Caters or Edelbrocks. They take air in, and as that air goes thru, it pulls fuel in too. It's no harder than that until you get into how they use that air. Holleys are designed for wide open throttle primarily. It's not that they dont run well at part throttle or for economy. But it's secondary to WOT. Carters were always designed for a wider performance envelope, and as a result, IMO anyway, will be a better street carb for 85% of engines in use. Remember, any combination of things done well is an exercise in compromise and will detract from any one thing being perfect. That whole "Jack of all trades, Master of none" deal...

[Fleet 500]

I am wondering what the cfm is of the original carb (Carter AFB #4131). Back then, they went by diameter in inches rather than cfm. It is 1.44" primary and 1.56" secondary.

[71chally416]

I think there are people who would have trouble with God supplying carbs, and then there's guys that can make a V8 run well with 4 drinking straws and some duct tape. Mind what you read, and try to research the "whys" behind the performance. Speedtalk "Advanced engine" section is very good for this. In terms of your car, I would go 750. Because that's what I've foiund works very well all around. Holleys are no different than Caters or Edelbrocks. They take air in, and as that air goes thru, it pulls fuel in too. It's no harder than that until you get into how they use that air. Holleys are designed for wide open throttle primarily. It's not that they dont run well at part throttle or for economy. But it's secondary to WOT. Carters were always designed for a wider performance envelope, and as a result, IMO anyway, will be a better street carb for 85% of engines in use. Remember, any combination of things done well is an exercise in compromise and will detract from any one thing being perfect. That whole "Jack of all trades, Master of none" deal...

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