What Cfm Needed?

J

JimmyDoLittle

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Aug 18, 2016

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Aug 20, 2016

#1

• Aug 20, 2016

• #1

Just got me my first mustang..67 with a 302(org 289)..The carb is 750cfm..am told that is to much..What is the correct cfm for this eng? Thanks..

 

dennis112

15 Year Member

May 15, 2005

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Amish Wonderland of Central PA.

Aug 21, 2016

#2

• Aug 21, 2016

• #2

JimmyDoLittle said:

Just got me my first mustang..67 with a 302(org 289)..The carb is 750cfm..am told that is to much..What is the correct cfm for this eng? Thanks..

Click to expand...

Probably on the big side unless your a drag racer and your car is set up for it. Original carbs were around 480cfm IIRC.

We would need to know more information about any changes that have been done to the motor, the car, and what you expect out of the car in order to give you a better answer.

 

J

JimmyDoLittle

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Aug 18, 2016

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Aug 21, 2016

#3

• Aug 21, 2016

• #3

Thanks Dennis, I'll get more info as I get more aquainted with it. The PO had it only 2 months and knows nothing..I think I'll keep the 302 as long as it behaves but gotta get the right carb on it..Will 600 CFM be ok?
what does IIRC mean?

 

dennis112

15 Year Member

May 15, 2005

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Aug 21, 2016

#4

• Aug 21, 2016

• #4

JimmyDoLittle said:

Thanks Dennis, I'll get more info as I get more aquainted with it. The PO had it only 2 months and knows nothing..I think I'll keep the 302 as long as it behaves but gotta get the right carb on it..Will 600 CFM be ok?
what does IIRC mean?

Click to expand...

Is you just want a simple answer, I'd say a 600 Holley with vacuum secondaries would work for you. If your car has an automatic, look for one that has the correct transmission kick down linkage for a Ford.

IIRC is short for "If I Recall Correctly." Its often used on social media when the details were once known, but over time from lack of use get fuzzy in the memory.

 

D

Dirty Rod

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Oct 26, 2014

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Aug 21, 2016

#5

• Aug 21, 2016

• #5

I had a 600 on mine until I went to bigger valves and a larger cam and then a 650 worked better.

 

rbohm

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Apr 12, 2002

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tucson,az

Aug 21, 2016

#6

• Aug 21, 2016

• #6

i need to know more about the engine combination before i can give you a proper recommendation.

1: what cam is used

2: what intake

3: what heads, and are they ported

4: what exhaust manifolds/headers

5: what compression ratio

 

zookeeper

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Aug 22, 2016

#7

• Aug 22, 2016

• #7

Just a little personal experience: I've used 600 cfm, vacuum secondary Holleys on lots of smaller (289-351) engines for years and have been happy. When I changed my car over to a single 4 barrel a couple years ago, I did some research and found QFT carbs. They're essentially a Holley-type carb but better. They aren't all that much more cost-wise and I'm thrilled with mine.

 

J

JimmyDoLittle

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Aug 18, 2016

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Aug 22, 2016

#8

• Aug 22, 2016

• #8

Thanks for the reply rbohm..the engine is a factory 302 out of a wreck with nothing built..long headers..don't know bout the intake nor comp..I have a fairly new 600 Quik Fuel sitting in the barn..Should this fit the Intake on it now?

 

J

JimmyDoLittle

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Aug 18, 2016

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Aug 22, 2016

#9

• Aug 22, 2016

• #9

zookeeper said:

Just a little personal experience: I've used 600 cfm, vacuum secondary Holleys on lots of smaller (289-351) engines for years and have been happy. When I changed my car over to a single 4 barrel a couple years ago, I did some research and found QFT carbs. They're essentially a Holley-type carb but better. They aren't all that much more cost-wise and I'm thrilled with mine.

Click to expand...

Yeah, I have a QF sitting on the shelf I will try..Thanks Zoo

 

Bullitt347

I have been doing it wrong this whole time

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Aug 22, 2016

#10

• Aug 22, 2016

• #10

It is all in how the carb is set up not so much the size of the carb. I could get a 1bb carb to work good on that engine, I could also get a 900 plus cfm carb to work good. It is about metering the fuel for the amount of air coming in, regardless of the cfm rating of the carb. All that being said...a smaller carb is easier to get to work right. So if you have the ability, the 750 cfm carb that is on the car can be made to work just fine.

 

rbohm

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tucson,az

Aug 22, 2016

#11

• Aug 22, 2016

• #11

JimmyDoLittle said:

Thanks for the reply rbohm..the engine is a factory 302 out of a wreck with nothing built..long headers..don't know bout the intake nor comp..I have a fairly new 600 Quik Fuel sitting in the barn..Should this fit the Intake on it now?

Click to expand...

since the engine is basically stock, i would go with the 600cfm carb you have instead of the 780. and both cars will fit the intake since they use the same bolt pattern.

 

Edbert

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Aug 24, 2016

#12

• Aug 24, 2016

• #12

I've got too much carb on a stout (420+ HP and TQ) 351W. My 750cfm had to be set pretty lean to get a good idle

 

J

JimmyDoLittle

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Aug 18, 2016

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Aug 24, 2016

#13

• Aug 24, 2016

• #13

Great Info..thank Y'all !