360->408 Builds at High Altitude Help!

Hi everyone! I am mapping out a 360->408 stroker build in Denver CO at 5500 feet. I have been playing around with Dynosim6 and the max horsepower I can seem to get at that altitude is ~450 HP naturally aspirated. Has anyone built any 500+ HP naturally aspirated small blocks at altitudes this high? If so what was your build? I am considering opting for a Paxton super charger system to get higher numbers. I would really like get over 500 HP and still have a streetable car (I do not plan on racing it just want to go fast on the road! haha)