If you use the theory of 2hp/cfm head flow, you need heads that flow 500 cfm, and a 400cid engine would have to spin around 12,000+ RPM.
Assuming a race block with 4.5" bore and 3.15" stroke (400.79 cid), 12,000 RPM, and a rod ratio of 2:1 The piston speed will be 6,300 fps, and piston acceleration will be 259,022 fps^2.

I think the above calculations are with a "normal" compression ratio of around 10-11:1.
If you push the compression ratio up to around 15:1+ you should hit the number with slightly less head CFM and engine RPM?
With the High piston speeds getting the rings to keep sealed will be a problem, need gas ported pistons and crankcase vacuum system, drysump oiling, etc, pretty much prostock type engine.