Technical Carter 4-barrel flow ratings

I posted this information in two different threads sometime ago, but it seems folks cannot find it, as I still get the questions, so reposting both WCFB and AFB in the same thread.

I am often asked "how big is my Carter carburetor"? Or "do you have a Carter CFM chart"?

Well, there are no exact answers of which I am aware, HOWEVER:

I researched ALL of the Carter prints of which are readily available to me (I still have about 12,000 microfilm frames on aperature cards which I cannot economically justify digitizing) and came up with the following:

If one does a mathematical comparison of published CFM ratings on the FEW that published ratings exist to the total area of the carburetor, one finds that ALL of the published ratings fall in the range from 106.1 to 107.8 CFM per cubic inch of venturi area.

I have charted the total venturii area on the genuine Carter AFB and WCFB carbs which are linked below. I am NOT going to categorically state positively that this approximation is exact; but if one would like a reasonable approximation that is probably much closer than most internet guesses, multiply the listed total venturi area by 107.

https://www.thecarburetorshop.com/AFB_flow_ratings.htm

https://www.thecarburetorshop.com/WCFB_flow_ratings.htm

Jon

 

Thanks for providing this information which is otherwise impossible to obtain by ordinary mortals!

 

I’ve never really cared about the flow of the 2 WCFB’s on my Ford Y-Block. I know the engine will take wide open throttle up to 100 mph and hearing 8 barrels is mighty sweet. The in town drivability of a 1953 carburetors amazes me for being what they were then.
I’m positive there were many inefficiencys to what carburetors were with later designs but I would never change the look.

 

Jimmy - I also delight with my 2x4 set-up.

Posting this information to help others do their own 2x4.

The WCFB was a good carb! The AFB slightly better, then Carter retrogressed with the OT AVS (ugh!), and then topped off their 4-barrels with the OT thermoquad which is my favorite 4-barrel for single street use.

Jon

 

We put a 455 HO Thermo-Quad equipped vehicle on the dyno rollers and we were amazed at the performance of the Thermo-Quad it was rated at 1100 cfm according to Peninsula Pontiac factory stiffs in the day it looked like a giant crab and that car literally jumped off the dyno rollers and that Thermo-Quad sounded like it could **** in an elephant . When we were done that carb had frost on it what a wonderful carb . Funny I never saw one again roll into my bay
Here is one I just found I'm guessing by the looks it's about an 800 CFM . Plastic body still in great shape

 

Thank you for your efforts Jon . I am utilizing your charting i.my engine design parameters and feel comfortable and confident since putting your numbers into my formulas . Great work !

 

Freddie - THANK YOU!

Jon

 

While I'm not a Carter guy, thank you for posting the info. I never know what I'll end up working on for others.

Devin

 

I think guys worry or concerned way too much over cfm ratings. Small base WCFB and Rochester 4GC’s were the go to carb into the mid 50’s and the large base into the 60’s didn’t flow much more if any and were used on engines over 350”.
It’s how one performs where you drive and use your engines. As the cylinder volume got bigger the vacuum signals got better too and milage and performance remained good to excellant.
It’s Venturi’s and atomization that makes engines run if 4 are good sometimes 8 are better..

 

Thanks for sharing your knowledge @carbking

 

Jimmy - the ratings are great for bench racing!

Saying "my red car is faster than your blue car" doesn't win any bench races.

But "my 1050 Dominator is bigger than your 400 WCFB" wins hands-down

Kind of like the kid that came to our local car club 40 years ago, and joined the club. When asked what he drove, he answered "I've got a big block 396 with three 4-barrels and fuel injection". After the laughter and jeering stopped, and he stopped blushing, he really turned out to be a pretty good kid!

Jon.

 

Ok I'll let the cat out of the hat . With the small base WCFB with less cfm rating ( 2016 ) I am going to see if you still have a second one I may procure for a dual carb intake I'm designing for a flathead so in my design parameters cfm rating is important since WCFBs have variants of cfm ratings so would be nice to utilize the one that fits the parameters .Don't worry this ' KID ' knows how to tune carbs ! Lol

 

Don’t know if I can ever find the photo but there is a flathead Ford V8 out there somewhere with 2 Holley 4000 “teapot” 4 barrels on an aluminum manifold. I believe it was on a closed cab pickup.