Whats the CFM for a 429 cadillac???

I have a stock 429 caddy motor out of a 64 deville and was wondering what the cfm was for the motor??? Thanks Jon

 

Hey Jon
Try this......CFM = [CID x RPM x VE] / [2 x 1728]
The trick here is to know your VE (volumetric efficiency). You could probably get by on this one with an estimate. Good luck, Mike

 

If you're thinking of buying an Edlebrock for it buy a 650 and a strip kit. It'll be happy when you find the right combination...

 

I think a 750 would be in order for a 429. That's a lot of cubes to feed. I've run a 600 on my 383, and I would definitely liked to have bought a bigger carb. The 383 doesn't rev much harder than the 429.

 

I believe the stock carb on my 429 was 750cfm, thats whats on there now anyway too. Its a cool motor, post pics!
-Anthony

 

The stock carb is a AFB part # 3655S and is rated at 500 cfm.
I have one built up if ya need one.

 

if it's a stocker, you sure won't need 750 cfm. Use the formula above based on theax rpm you think you will ever use and multiply the results by .85 to estimate what a stocker needs based on 85% VE. Anything bigger will kill low end torque and cause terrible fuel milage since you'll have your foot in it all the time to
make it up.
I ran a 600 holley on a 460 for years and got great milage in an F-250.

 

I have always used a simpler formula.

(Displacement X Max RPM) / 3456 = Target CFM

So as an example:

(429C.I.D X 5k RPM) / 3456 = 620.6597222222 CFM

So if you use that formula. A 650 should be about right.

 

I run a 600 cfm vac sec Holley on My 429. With 2.79 rear gears ran 15.08 in the qtr and got 14 MPG at 70 on the freeway. Works for Me. FEDER

 

I had a buddy with a 429. We put a 600 edlebrock on it, ran strong!

 

I've been driving mine with a 650 cfm electric choke for 3 years trouble free. Edelbrock. Make sure to block the heat cross over on the carb base.

 

If you see a wide variety of sizes used on engines, the reason is that the modifications, the type of manifold, the rpm range, the type of transmission, the type of carburetor, and what you will use it for, all will change the size you need.

That is why you may see something like a 350 chevy modified for perfomance, with everything from a 500 CFM to 1500 CFM.

If your engine is stock, and will see only street use, stay with the orignial size, or slightly larger to improve performance. Looks like 500-650.