Many think

"if I get a bigger carburetor, I'll go faster"

That's a Myth

To go faster

There is a way to go faster by having the exact right size carburetor.

Your engine

being a certain size, can only pump through so much air.


If you get the exact proper size of carburetor to feed the exact amount of air your engine pumps through it, you score.

Here's how to figure it out —

First, figure out the exact size of your engine

C.I.D. - Cubic Inch Displacement

C.I.D. = Bore squared x stroke x .7854 x number of cylinders

e.g.-----------bore x bore x stroke x .7854 x 8 cyl.

Small Block Chev = 4 x 4 x 3.484 x .7854 x 8 = 350.25 cid

Then use this formula

The following formula will define the C.F.M. (cubic feet per minute) of air/fuel mixture your engine draws based upon your engines specific parameters. You can now determine what size of carburetor you should use for your application.

C.F.M. calculator

C.F.M. = Engine Size (C.I.D.) times maximum R.P.M. divided by 3456

e.g. (S.B.C.)-------350cid x 6000rpm ÷ 3456 = 608 c.f.m.


Using a carburetor that is too large can be harmful to your engine as most larger carburetors are often jetted richer which will cause your spark plugs to foul and will promote fuel wash resulting in piston ring and cylinder wall damage.

C.F.M. Chart

CFM Chart

To convert cc's to CID
1000 cc's = 1 L = 61 CID

so - 1000 cc's X .061 = 61 CID