Papitto had noticed uneven burn patterns in the combustion chamber that were indicative of mixture problems, and had always believed there was 40-50 hp in the engine if he could straighten that out. Three intake manifolds and various injector-targeting strategies returned no improvement, but switching to a carburetor did just what he was looking for, that being better mixtures and the 50 hp he estimated was there for the taking.
Papitto was quick to point out, however, that with any sort of power adder, EFI is the way to go. His 5.4-liter DOHC modular engine is normally aspirated and currently generates nearly 600 hp to the tires. Additionally, in a well-prepared drag race engine, the useable operating range is a window of about 1,500-2,000 rpm, an area in which a carburetor can, in many cases, equal or surpass EFI in performance.
EFI has its proponents, too, with Turbo People's Job Spetter Jr. making the statement that there is no reason to run carburetion any more. Spetter's wizardry with Accel DFI and FAST electronic engine management systems has propelled numerous EFI cars to victories in a number of drag racing categories.
Corroborating Spetter's statement are Street Warrior champ Darrell Peterson and Street Outlaw competitor Cale Aronson, both of whom run fuel injection on their normally aspirated racing powerplants with great results.
The long and short of it all is that an EFI-to-carburetion switch is not a decision that should be taken lightly. Do your research and have a definitive plan for your project's performance.