Where's the flow go?

[zerfetzen]

This is probably a dumb question, but hey, I'm learning :

If flow is measured in CFM, then where does the flow go when you have a Holley 750DP (flowing in 750 CFM) feeding cylinder heads that flow, say 212 CFM?  In my book, that leaves an extra 538 CFM unaccounted for.  Not to mention the intake CFM.  It seems like everything (carb, intake, heads) should all be able to handle 750 CFM, or the carb's too big (I know it's not, but just don't understand flow).

Any takers?  Thanks.

[Hopalong]

That would be 212 cfm per intake port, and that is only at a measured valve opening.  So 8 intake ports would need 2176 cfm, but not all are open at the same time, so everything works out.  Maybe it's just mystic voodoo!

[Oldschool]

  

[zerfetzen]

Good stuff, I knew it made sense somehow. 

[moper]

Then it should really confuse you to know your "750cfm Holley" really only flows about 690...lol. Because in the earlier versions, Holley did not use a liquid to flow thier carbs. (neither did anyone else, really) so only using air, they measured 750cfm at wide open throttle. I'm not sure of the depression they used, I believe it's 10". When you add in the liquid fuel, that takes up space, and the less air volume is the true flow rate of the carb. Holley HPs, Avengers, and BG Demons along with all custom carbs are now wet flowed, using a safer fluid than gasoline, but that mimics it in every other way. So,  comparing a 750 Demon and a 3310 750 Holley, the Demon is a bigger carb by 8% or so.   

[Chryco Psycho]

Holley used 3" on 2 bbls & 1.5" on 4 bbls so comparing a 6 pack @ 1350 cfm to a 4 bbl doesn1t work either , the sixpack will flow closer to 1000 cfm flowed as a 4 bbl