HIGHLANDS RANCH — Mountain Vista, an unstoppable football machine, has put Class 5A on championship notice. In front of a sellout, standing-room-only crowd at Halftime Help Stadium on Friday, with fans spilling into the aisles and peering over the fences, Mountain Vista met the moment — and more — in its highly anticipated homecoming game against Valor Christian. The Golden Eagles raced to a 27-0 lead early in the second quarter, and Mountain Vista’s explosive offense didn’t let up en route to a 62-21 running-clock boat racing that is a record for points scored against Valor Christian.