[Judgement]

So I finally have my GTO convertible running but not well! I've built a stroked out Pontiac 400 to 463, engine dyno runs showed the the motor put out 520 hp and 613 tq with a carb. In the car I am running FAST EZ EFI and a 4l80e transmission. Now here is the issue, I have driven the car around for a while enough time for the computer to learn but it's not! If I am driving around the car runs great but when I hammer down on it the car falls on its face!! I'm losing at least 150 to 200 hp some where and I can't find it, can this system be tuned any other way? I NEED HELP PLEASE!!!!