garbage in garbage out. If you have the head flow numbers, pipemax has a calculator to predict volumetric efficiency. which helps get the numbers closer. I mainly use it to predict header tube length as the program calculates the resonance of the gasses, which plays a big part in tuning the headers to the cam and intake to make them work together. 1000 hp is around 2 hp per cubic inch for the combo mentioned, you have to have all your ducks in a row to make that level of power. Again all the computer programs made are just tools to help you get the combo close. Then time on a dyno gets it better, then the race track tuning gets it as good as it can get. I personally have never made 2 HP per cubic inch with out some dyno time and changing a few parts and playing with cam timing.