a single plane with mech secondary carb will outflow (cfm) most of the efi kits, because they are designed for street use. not the electronics part, but the actual size of the inlets/venturi/etc. the physical part is not sized big for very high rpm / high output use.
your mileage will be quite low though haha.
so really, it depends on what you plan on doing with the car. drag race, mileage is your last concern, high output best ET is what matters.
street use, sure you want something peppy but good mileage too and something that cruises smoothly. you want something that can sneak out of the neighborhood without having to run 3000rpm's in case you want to go out at 6:30 am to get coffee and not wake everyone up lol.
so EFI is fine.
i dont buy into the crap that newer is better though. "new technology" does nothing for me. so if i WAS racing on the strip constantly and ET mattered and i wanted a bulletproof setup i probably would not go EFI and probably would not run nitrous. i doubt i would invest in a new hemi since it's not designed to be a racing engine. for the street it's great.
Ummm, no.
A carburetor will not, cannot, and does not outflow the throttle bodies available for most EFI equipped cars today. For example the bone stock 81mm throttle body found on the modern hemi will flow over 900 cfm. 90mm throttle bodies flow over 1100 cfm.
http://kennebell.net/KBWebsite/Tech_Info_pg/layouts/turns_pg.htm
I don't think anyone running a naturally aspirated 5.7 or 6.1 Hemi is running a 900 cfm holley. Why? Because carburetors are simply a mechanical computer. The carburetor uses the pressure drop between the plenum and the atmosphere to draw fuel into the motor. This is called the venturi effect. As air travels through the restriction (ie the carb) it draws fuel through the jets and ports inside the carb into the manifold. If there is not pressure drop, or no restriction, no fuel is drawn into the motor. Now when you mash the go pedal for a brief moment there is in fact no pressure drop, vacuum falls to zero, and thus there is nothing to pull fuel into the motor. So carburetor designers add accelerator squirters to compensate for the lack of a signal or draw.
So if a carburetor doesn't out-flow a throttle body how come in test after test a carbureted engine typically makes 10 to 15 more HP? Since a carburetor atomizes the fuel in the plenum this atomization has the ability to cool the inlet charge enough to create a slightly denser intake charge which results in slightly more HP. When a gas expands (and fuel transitioning from a liquid state to a gaseous state is an expanding gas) it removes heat (gets colder), this cooling effect cools the entire intake charge.
If fuel atomization can have the ability to cool the intake charge and create more power, why don't automotive engineers place the injectors at the top of the intake runner, so that fuel can cool the intake charge and give us a little bit of free HP? In a port injected motor designers have figured out that aiming the injector at the back of the intake valve, and firing the valve when the valve is closed, allows the fuel to hit the backside of the hot (not exhaust valve hot, but still hot) intake valve and thus atomize more completely. This means that the car will drive well and there won't be any fuel puddling or other problems. In addition this setup allows for excellent driveability under a wide variety of circumstances.
Many custom intake manifolds for racing do infact move the injectors up the runners to take advantage of the cooling effect. For example F1 engines actually mount the injectors ABOVE the throttle plate. As a result, in my view if you were able to create an apples to apples comparison between an injection setup with the injectors strategically placed and a carbureted motor you'd find that the HP differential disappears. In fact given the ability to mount SEVERAL sets of injectors it would seem likely that an EFI motor would produce significantly more HP, especially considering that it doesn't have the obstruction created by a carburetor.
Further, since the difference is basically the difference in intake temp, we have to distinguish between a dyno number and the actual number from the car in a real world situation. A carbed motor with an open element air cleaner drawing hot underhood air may make less HP than an EFI motor with a cold air kit. Obviously, cold air kits exist for carbs too, but my larger point is that 15 HP advantage can suddenly disappear if a tuner lacks the basic understanding of the importance of underhood temperature.
Finally, again talking about the real world imagine you're racing Pikes Peak and going from 9000' to 14,000', no carburetor in the world could give you peak (pun intended) performance with a 5000' elevation change. You would have to pick a jet setup that struck a balance between performance at 9000' and 14,000'. With fuel injection, and dual MAP sensors the computer can send differing amounts of fuel to the motor depending upon real changes air density depending upon altitude. In addition, the computer can also take into consideration changes in air temp, and water temp. All of these things make EFI number more repeatable, more consistent.
The last time I checked repeatability and consistency were two critical factors in winning drag races.
In conclusion, your statement that the Gen III hemi is not suitable for racing is simply wrong. The stock block is capable of handling in excess of 1000 HP. There are innumerable 4000 pound Chargers, Challengers, Jeeps, and Magnums running 9 second quarter mile times. Any motor that can propel 4000 lbs to 150 MPH is entirely suited to racing.
Regards,
Joe Dokes
I've heard plenty of carbed hemi's on youtube, they sound like a NASCAR when they smash the go pedal. I've posted plenty about my preference for EFI, but in all honesty, sticking with EFI probably cost me an extra year in my build. 
