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Carb sizing

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Cool53:
Amen, Mike.

Cool53:
But one carb might be better not so much because of size but by what parts are used. Straight leg boosters won't pull main fuel as quickly as down leg boosters, and annular discharge boosters will bring a 750 down to about a 680, just because they are much bigger and restrict air flow. Hat makes a much crisper throttle response, gives better fuel atomization. But companies like AED make such terrific changes to the area under the centuries that carb sizing on a conventional Holley gets thrown out the window. But stay smaller.

TFoch:
So using the formula Moose posted for my 283 I should be looking for a Holley 390 CFM?

CFM = Displacement X RPM X VE / 3456
Example: CFM = 350 CI X 6000 RPM X 90% Volumetric Efficiency / 3456
CFM = 350 X 6000 X .90 / 3456 = 546.87
CFM = 546.87

CFM = 283 X 5000 X .85 / 3456 = 348.02

Cool53:
It still depends on compression ratio, manual or auto, if auto what stall speed, etc. but if it's stock it's better to go small.

chopper526:
Helpful site Cool53. I checked it out and I may be a little under-carbureted, but I'm happy.

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