Diff Between 2 Barrel vs 4 Barrel CFM Rating

2 barrel carbs are rated differently than 4 barrel carbs. Something about the 2 barrels tested @ "twice the pressure drop". Could some one put this in easily understood language? I would like to know what the cfms of the Holley 350 & 500 2 barrels are in 4 barrel measurement.

Thanks in advance, John

 

Post #17 in this thread might be what you're looking for? Panic wasn't always the most pleasant/patient member, but he seemed well read up on the technical side of things.

http://www.jalopyjournal.com/forum/showthread.php?t=327843&highlight=cfm+ratings

 

BTT for the morning crew.

 

Here Ya Go....
http://www.candsspecialties.com/ratings.html
Hope that helps.....

Over at SpeedTalk, I believe it was a couple of months ago, several other Motor builders and myself were thrashing it out over there about the CFM ratings, the correct way to pick carbs and all....Its one of the biggest mistakes made in the HotRod and performance car industry. Everyone always thinks bigger is better, which isn't true.
Sure, you can 'tune down' a carb to a specific amount of fuel to a certain amount of air....after that....your killing performance if the cfm is way off....

 

John - this article may (or may not) help:

http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm

CFM figures remind me of the line attributed to Mark Twain: "Figures don't lie, but liars figure"!

Jon.