The YFA Carter ratings are from Ak Miller, and differ from the SAE and Holley SA book ratings, but all later carbs are 195, 202 or 233 cfm at 3" Hg according to my three sources. Its very important that all Ford carbs were supllied thru Autolie in 1970, so there is confusion on what is what.
The ratings differ from the Ford Falcon 6 Performance Handbook...the ratings from that book are SAE Ratings via an approved SAE source. I believe the Ford Falcon 6 Performance Handbook, but Ak Miller was employed by Autolite, so his ratings are CFYI.
See Page 42 from Peterson Publishing's "The Complete Ford Book" C.1970
https://www.jalopyjournal.com/forum/thr ... 452/page-2
Your conversion is exactly like
Frankenstang's
viewtopic.php?f=1&t=72607&p=562727#p562727
and Asa's.
viewtopic.php?f=1&t=76871 and
viewtopic.php?f=1&t=76774
All tuning problems with YFA's are just PCV, ignition and metering rod "needle" and jet specification settings. There is a little in the rebuilding process, and about 85% of all rebuilt YFA carbs are in fact wrong for a small log 65 200 Mustang.
Ford got forced into using Carter YFA carbs by the need to hook into 1968 Autolite ignition and the IMCO and Thermactor hookups, right at the same time Chevrolet stopped using Carter carbs (although Carter still made Rochester carbs, millions of them, for Chevy and GM for many years)
Once you've got the right basic adaptor to mount it with enough proper clearance for the throttle blade...you got it made.
There is a reason this carb survived from 1950 to 1989...it was a brilliant, accurate carb with a lot of development work done on it by the Big Four automakers. And the basic design is very, very sound.