You're going to be sorry that I beat you to this. I'm going to go out on a limb and make an outrageous prediction. At a FIA event on good salt, 500 mph, NO WORRIES.
Speed Demon seemed to respond well to the lower corrected altitude (good air for HP) with no ill affect from the denser air. I am extremely happy for an older fellow that has been a hot rodder all his life and is realizing his ultimate dream. Congratulations to George Poteet