Both the Carter YF/YFA and the Holley 1946 are for the later heads (w/the 1.75" carb hole and wider bolt spacing).
I have the 1946, and I like it. Getting the choke set to my liking was the most difficult part. Of course, this isn't a Holley 1946-specific problem - I prefer a manual choke on any carb. But I digress...
I can't give an opinion of the Carter YF/YFA as I've never had one. A lot have used this carb. with good results. But, as with anything, each carb has certain advantages and disadvantages.
Both of these carbs. were designed to utilize the cable throttle linkage setup. If switching to either one, I would advise getting the cable setup (everything from the pedal to the cable mounting bracket) from a Fairmont, Granada, etc. or get an aftermarket setup. It's very easy to install. However, it's not necessary to convert. I personally like it b/c there is no worn feeling as with the old linkage. (Of course I had the Falcon bellcrank linkage, which has more wear points.) It's more responsive to small changes in the pedal position.
Another thing you have to consider is your distributor. If it hasn't been changed, you have the Loadomatic vacuum advance-only distributor. This dist. and the Autolite 1100 were designed to work together, utilizing the spark control valve in the 1100. If the carb is changed to one that doesn't have a spark control valve, the vacuum signals sent to the dizzy aren't quite the same. It will work: I ran my 1946 with the Loadomatic for over 2 years with no "problems." But last year I finally converted to a '68-up dual advance (meaning centrifugal+vacuum) dizzy. I noticed a definite improvement by changing distributors.