I run aftermarket EFI on my GT40 replica IR intake.
All i can say is its awesome. The throttle reponse is instant. I run a Microtech Programmable ecu with an Alpha N or TPS tune as the motor has little manifold vacuum for MAP sensing. ai do all my tuning on a Mates Dyno and I make good power ,493hp at the wheels so around 600hp at the flywheel.
video of GT40 flat from 1st to 5th gears