Hi --  I have a marinized 312 that uses 2 single barrel Carter YH carbs.  I've searched quite extensively to find the CFM rating on these carbs, but haven't had a lot of success.

Thought maybe someone here could help me!

Appreciate any replies! 

You can get a rough idea by measuring the venturi area of the single bbl and comparing it to a the verturi area of a known two bbl carb.  There is some effect based on the design of the boosters etc in the venturi but for an approximation calculate the ratio of the areas.  Remember that a two bbl carb is rated at 3"hg, I would guess that the single throat YH would be rated at 3" also.

A 4 bbl is rated at 1.5"hg.  This means that a 2 bbl would flow about 71% of a 4 bbl with the same nominal CFM rating.  For example a 3 deuce setup with carbs rated at 150 CFM would not be the same as a 4 bbl with a 450 CFM rating. The 3/2 setup will flow 318 CFM if rated at the same differential pressure as the 4bbl. 

Doug T

The Highlands, Louisville, Ky.

You might try the website for Allstate Carburetors.(allcarbs.com).He is very knowledgeable about most carbs.Try an email from the site.

  

Another place you could try  would be some of the Corvette sites, these are the same carbs. the "Blue Flame" 235 sixs had in '53-'55.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

I seem to recall reading somewhere that there flow rate is quite low, probably under 150cfm., considering the Blue Flame 6 used 3 of them, it's likely the case.

Paul

Also used on a draw through application in the Corvair Spyders. The turbochaged 150 or 180 gross hp rated versions. 

Frank/Rebop

Bristol, In ( by Elkhart)