Carburetion Vs. Injection
Converting to EFI is not a decision that should be based upon looking for outrageous power gains, but rather for the best drivability and efficiency gains possible. The naked truth is, given exactly the same components, the power of a perfectly tuned carburetor will be virtually identical to an EFI system. One of the key differences is an EFI system is "smart" and once programmed correctly, will always be in perfect tune, no matter how the operating conditions of temperature and air density changes. We installed a Demon four-barrel carburetor to the tuned EFI system on the dyno just to compare the wide-open-throttle output. Not surprisingly, with the combination otherwise identical, the power curve was virtually unchanged, with the EFI gaining a modest advantage in low-speed torque. However, by taking advantage of the intake manifold design flexibility available when running EFI, the power characteristics can be changed significantly. Modern plenum ram manifolds of the type used on the LS-family of engines are a good example. This design takes positive advantage of inertia ram tuning for a healthy boost in torque, but such a manifold layout would be impossible in a carbureted application.
While an EFI system can be tuned to a fine set of parameters at the keyboard of a computer, a carburetor is a mechanical device with fuel curve adjustments primarily handled by changing jets, altering the orifice restricting fuel flow. Tuned for a perfect air/fuel ratio, output is about equivalent when considering full-throttle horsepower and torque, if all else in the engine remains unchanged.