Carburetor cfm calculator
Carb selection and worries of being too small or too big and how to size has been around for decades, but now with so many sizes and styles you gotta decide on more than just cfm. Pure street use:
The old but still relevant from 1978 “Mopar Performance” book gets it right IMO:
Keeping the above in mind then you could move on to formulas and calculations (and if you know the specs for the rest of the “package”) see what cfm you come up with.
As far as calculations go I like Vizards carb selection method which uses a correction factor.
Figure where your peak power rpm is and Then run the calculation with the conversion factor:
Depending on your cams duration @.050” and cylinder heads, for example you might have a correction factor of about 1.01 so:
CFM= 360 x 5500 x 1.01
—————————
3456
Running the calc yields approx. 580 CFM
Take the various calculations and compare, and with those numbers use the Mopar Performance along others way of thinking and err on the side of conservative. Unless you’re drag racing and need ever last ounce of upper rpm power......
For what you have, looks like you’d be using:
Holley: 600-650
Edelbrock: 600-650
Street Demon: 625
And call it great!
Carb selection and worries of being too small or too big and how to size has been around for decades, but now with so many sizes and styles you gotta decide on more than just cfm. Pure street use:
The old but still relevant from 1978 “Mopar Performance” book gets it right IMO:
Keeping the above in mind then you could move on to formulas and calculations (and if you know the specs for the rest of the “package”) see what cfm you come up with.
As far as calculations go I like Vizards carb selection method which uses a correction factor.
Figure where your peak power rpm is and Then run the calculation with the conversion factor:
Depending on your cams duration @.050” and cylinder heads, for example you might have a correction factor of about 1.01 so:
CFM= 360 x 5500 x 1.01
—————————
3456
Running the calc yields approx. 580 CFM
Take the various calculations and compare, and with those numbers use the Mopar Performance along others way of thinking and err on the side of conservative. Unless you’re drag racing and need ever last ounce of upper rpm power......
For what you have, looks like you’d be using:
Holley: 600-650
Edelbrock: 600-650
Street Demon: 625
And call it great!
