I don`t know what the HP numbers would be going to a carb...depends on the carb and intake you use,but you will lose a LOT of torque compared to the EFI,and have driveability issues,eg,poorer hot/cold starting,and engine response compared to EFI.
I wouldn`t even personally consider switching from EFI to carb,especially for a street car.
If you have a properly tuned carb, it runs awsome. We switched from carb to EFI on an old bronco and my buddy thought it ran worse. It just depends. Different strokes for different people...er folks...whatever.
I am with Grady - since we are older than some peeps on here and cut out teeth on carbs (I might add that I had to learn EFI like some of you younger guys are learning carbs) we see it a lil' different.
The thing is that carbs are kinda finicky - atleast for me they always were (I used to fight cold weather vs hot weather jetting, etc. When tuned good for 90* ambient temps, the car ran like poo when it was 15* out). And carbs tend to require more compromise - EFI can allow a 1000 HP beast to idle and run at part throttle like a stocker. Or run great when temps are 30*F or 100*F, at sea level or 5000' high. Amazing!
I kinda see an A9L swap as a step down, as would be SD (I LOVE SD), and a carb is a couple steps down for a daily driver (weekend toys are different).
My 2nd car was a 1966 chevy caprice (think 66 impala) that I had a 350/350th put into. The car had a 650 holly with no choke....
fun learner...but the throt. was very hard to get the response out of esp. with a 2ton 2door like mine. Fought a lag with the carb going from part to WOT ALOT.
I am with the others on this...keep carbs on the oldies or track cars...EFI can go both ways though. But dont carb a daily EFI car, at first it will look cheap but after looking at all the things to do it proper its not all that cheap just to get worse mpg, more drivability issues, and remember smog goes out the door at this time.