by dave-r » 10 Feb 2004 15:53
2bbl carbs are measured at a higher pressure drop than 4bbl carbs so you cannot make a direct comparison of the cfm ratings between the two.
However you can convert 2bbl and 4bbl cfm rates from one to the other (as per my math speadsheet you can find various links to).
First of all the carbs are the same on the 340 as the 440. Just jetted different and I doubt the vacuum operated outers open that much on the 340.
The two outer carbs in a six pack are 500cfm each (2bbl rating) and the center is 350cfm. Total 1350cfm
However when you convert that to the way that 4bbl carbs are rated it works out as 2 x 357cfm and 250cfm. Total 964cfm.