What carb for 440
- Thread starter Napoleon1991
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Geoff 2
Well-Known Member
So you need a big carb to make HP?
SBC made 465 hp using four 48 IDA Weber carbs. Each cyl draws from just one barrel, which flow just under 300 cfm. Yes, that's right, 465 hp from under 300 cfm; on the same engine, a 850 Holley made 430 hp & was also down about 25 ft lb in tq.......
SBC made 465 hp using four 48 IDA Weber carbs. Each cyl draws from just one barrel, which flow just under 300 cfm. Yes, that's right, 465 hp from under 300 cfm; on the same engine, a 850 Holley made 430 hp & was also down about 25 ft lb in tq.......
Curiousyellow71
Well-Known Member
I got the hp wrong he made 568hp with the avs on top of it through the manifolds w his iron intake. To keep w the rules I believe tbe AVS butterflies are stock 383 size...again this is F.A.S.T. racing lots of internals changes allowed. Just stock appearing on the outside. We have a car we are going to "try" to compete...we have a thermoquad. I would NOT want to trade. Although his AVS flows well beyond stock.
The point of choosing cfm carb sizing is their is not necessarily a downside to a oversized carburetor. Some of the most quick accelerating cars I have been around the carb cfms were indeed oversized. There really is much more going on then cfm. Six pack is a great example. A bad tuned carb is a going to be poor no matter what is going on under it. This is Bill's RR. Maybe he will chime in.
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A 48 is 340 cfm.....and isn't a IDA 48 a two barrel setup? So using 4 of those would be 1200 cfm or more since they are rated at 340?
Curiousyellow71
Well-Known Member
I think a weber can vary depending on how it's choke is set up. We had a 327 in a road race car with 4 webers. I think ours were 300 cfm per barrel. It had 4 carbs 8 barrels for a 2400 cfm total. I think most weber 48s are larger even then 380 cfm! I do not see it helping the case of small is better? The webers x4 intake was Kool but impractical. Certainly not a weber expert. I never got to play with it. The weber set up was sold, looked identical to this one below. It was on a car like this....sitting in our trailer.
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Some Car Guy
Well-Known Member
Headers add some hp, but are really a mod to get more torque.
PsyOps
Well-Known Member
OP's info: "Engine is a 440, 10:1 compression with a voodoo 703 cam. It has TTI headers, a performer intake..." and "The car isn’t raced at all, it’s just a cruiser so I’m looking for something simple and reliable that will still perform well when I decide to mash the skinny pedal." I didn't see a post correcting the intake to a Performer RPM so we're talking something slightly better than stock cast iron. As WileERobby said, I'd find a BB TQ. Barring that, I'd opt for the AVS2 with cfm choice (650 or 800) up to you. Please let us know what you end up with and how it is working out so we can add your real world experience to the site's knowledge base.
BSB67
Well-Known Member
With 800 cfm, or more. Bill's 600hp would mean that the 955 cfm FAST guys are making 710 hp. That's more than 15 hp, right? Thanks for pointing that out.
And, you're the one making it about Holley verses everything Carter and Edelbrock, not me. I personally like them all. I currently have 13 or 14 Muscle car/high performance carbs, about half are Holleys. I honestly like all of them. Some are slightly better suited then others, depending on the application and desired outcome. You'll never see me picking sides in a carb brand discussion. And, if I posted my least favorite carb, that would start another **** show, and not with you.
But to think size does not matter when seeking max potential power is simply rediculous.
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BSB67
Well-Known Member
That makes more sense, based on his weight and mph, and that puts the 955 cfm guys probably closer to 670 hp.
Curiousyellow71
Well-Known Member
Anyone remember the Predator?
Variable venturi carb...incredibly responsive with 1000cfm you could run it on about anything. On a mild 440 we switched out a Avs on a 70 challenger..went from a 14.1 to a 13.7! Later we tried it on our 510 w slicks and it cleaned out the 8 3/4. Predators were great and terrible ALL at the same time! Last time we ran one it filled the engine w gas and it bent a rod.Lol
...not recommending it.Lol
Variable venturi carb...incredibly responsive with 1000cfm you could run it on about anything. On a mild 440 we switched out a Avs on a 70 challenger..went from a 14.1 to a 13.7! Later we tried it on our 510 w slicks and it cleaned out the 8 3/4. Predators were great and terrible ALL at the same time! Last time we ran one it filled the engine w gas and it bent a rod.Lol
...not recommending it.Lol
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I remember them.....and didn't it get nick named 'the toilet' ?
mountain33
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Geoff 2
Well-Known Member
Cranky,
Post #84. Nope, the 48 IDA flows 296 cfm [ per barrel, with 38mm chokes. ] The four Webers were an IR system [ independent runner ]. Each cyl sees ONE carb barrel, in this case 290 cfm.
Holley made a 4500 IR system carb, #6214, rated at 1150 cfm. Used as a true IR carb, each cyl sees 288 cfm.
Post #84. Nope, the 48 IDA flows 296 cfm [ per barrel, with 38mm chokes. ] The four Webers were an IR system [ independent runner ]. Each cyl sees ONE carb barrel, in this case 290 cfm.
Holley made a 4500 IR system carb, #6214, rated at 1150 cfm. Used as a true IR carb, each cyl sees 288 cfm.
66 Sat
Well-Known Member
So if the small block Chevy made 465hp under this arrangement, how much cfm does each cylinder see using a 600 cfm 4 barrel carb on a dual plane manifold?
Just for comparison purposes, so we're comparing apples with apples.
Curiousyellow71
Well-Known Member
On a 8 barrel weber each barrel has to feed the demand of one cylinder. Each cylinder and carb is independent of each other. So 296 cfm is all one cylinder has available, it only draws from the carb every other revolution on a 4 stroke.
A open plenum 4 barrel all 8 cylinders draw from the whole carb. The weber only see's vacuum when one cylinder is sucking on intake stroke. A 4 barrel is feeding the demand of all 8 and sharing it(in a sense).
Feeding cylinders individually has its advantages... but feeding 8 cylinders at one time also has its advantages. Simplicity for one.
To get a cfm more info is needed. Need v.e. and rpm. Probably another equation out there but this comes to mind:
A open plenum 4 barrel all 8 cylinders draw from the whole carb. The weber only see's vacuum when one cylinder is sucking on intake stroke. A 4 barrel is feeding the demand of all 8 and sharing it(in a sense).
Feeding cylinders individually has its advantages... but feeding 8 cylinders at one time also has its advantages. Simplicity for one.
FWIW..I dont think there is a way to compare it other then a dyno..it is apples and oranges.
To get a cfm more info is needed. Need v.e. and rpm. Probably another equation out there but this comes to mind:
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top wrench
New Member
AVS or Thermoquad the air valve is adjustable they are 750 thru 850 cfm and very adjustable idle and low speed jets find someone in your area how knows how
Napoleon1991
Well-Known Member
That actually brings up another question. Would i see significant gains in switching from the performer intake to the performer rpm with my current setup?
The answer up to you. Where do you want the power range. Hi, or lo.
Some Car Guy
Well-Known Member
The RPM manifold is probably the best street intake for a mopar ever made. I ran one back to back on my 71 cuda against a six pack. The rpm was noticeably stronger. I didn’t take it to the track with the six pack unfortunately so don’t have that data point. You could just feel it and it was no doubt.
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