I would go with the B1Mc motor with lower compression pistons. It is easier to put a mild cam in it and add a blower to get the 1200 hp over the others. Cubes rule, blown or not. Heads likewise. The more power you want to make, the better they need to be. I am partial to screw type blowers. Whipple has sizes that will accommodate what you want, and not break a sweat doing it. If you build an 800 hp pump gas motor, then put 7.5 psi boost to it, with an intercooler it will produce about an additional 60 percent more hp. That would get you what you want with insane off idle torque to boot.