Calender photo spot for next year.... did your carb act up at that height???
They just start running richer as the oxygen level thins out. At 10,000 you only need to ingest about half the gas you do at sea level.
They have been racing up Pikes Peak for over 80 years now. 14,000 ft and carbs isn't an ideal combination, but it can be done without too many issues, just a lot of black smoke.