A generation ago Archie San Romani of Kansas, the man in the Olympic sweat suit, was one of the fleetest milers on the American track; a consistent rival of Glenn Cunningham (also of Kansas) in lowering the time for the outdoor mile to around 4:07. Archie never thought it fair to expect too much in the way of track performance from his only son, Archie Jr., or to overurge him into a track career. But the other day Archie Jr., a Wichita high school senior, laced on his size-13 spikes at the Hutchinson Relays and ran a mile in 4:13.6. It was the fastest schoolboy mile ever run in Kansas, only 0.4 second off the national schoolboy mark, which Archie Jr. might well equal this year. Archie Sr., whose best high school mile was 4:36.3, now finds himself-the father of what an on-the-scene observer calls "the country's only born miler and the best mile prospect the country ever had," and it leaves him a little incredulous: "I'm living my life over again." Says Archie Jr.: "It's Dad's dinner table chats that help me most."