Any one know how many cfm the carter carbs had on the 440's?
Something I don't understand is I had straight exhaust tips on my 67 R/t and when I drove with the windows open I got exhaust smell in the car.
I then went to turn down tips and the problem went away.

 

My understanding is Straight tips need to be extended about 4" past the bumper. Turn down can exit at the bumper. AVS carbs were around 650 cfm

 

I used the formula and came up with 550cfm for 440 @ 6000 rpm. I put a edelbrock 1406 600 cfm on runs perfect. I was told to use a 750 cfm. The straight tips ended at the bumper. That was my problem. I was told that bigger than needed wasn't always better on carbs. Thanks!!

 

if iam right the1967 R/T 440. didnt have a big carb, like the 68 AVS, the 67 AFB has a air valve over the rear plates, that is the only AFB with that, i think. i have set an AFB float level at 5/16, with good out come, stock is 7/32.

 

I am not sure that these simple formulas (engine displacement x rpm x volumetric efficiency) are sufficient, as the air flow through the engine is not constant but pulsating. Also, the carburetors may not always have an honest rating. Anyway, I have a mildly built 68 440 (.477 intake lift, larger valves, a bit higher compression) and I have a 750 AFB on it. I also recently installed a vacuum gage. I will be testing the car at WOT and see what the vacuum is in the 4000-5000 range. If it is under 1.0 or 1.5 inches, then I do not need more carburetor. But if it is more than that, bigger carb will help.


My other 440 (which I do not know its internals, but my guess is it has a cam step up or two from the stock 0.425" intake lift) has a 750 (or 850) Q-jet, and seems to like it.


Also, the square bore AVS's were also 750 cfm. But these are expensive, because they were OEM on the 68-70 Chargers & GTX's etc.

 

 

ban him