Forget about 900 HP
You can't get blood out of a stone. In talking to the manufacturers, they are lucky to get 750 HP out of the engine with the parameters they must meet, and that is for road courses, not high speed ovals where the engine is at max RPM for three hours.
However, if they trash the hideous looking new Dallara and chalk it up to a mistake, they could use the existing car another year and have Dallara go back and design the car like the one below. With the covered wheels and closed canopy the car will have a much lower drag coefficient and go around the race track as if it had 900 HP. The driver will be safer with the closed canopy, there will be no tire-to-tire contact because the tires are enclosed, and if you bump a little, like NASCAR, the car may wiggle and keep going. Oh, and BTW, us IndyCar fans would absolutely love a car as futuristic as that. Is that car awesome looking or what? IndyCar – When in doubt, just do what's right. Mordichai Rosen