As reason replaces instinct in the development of mankind, much is gained. However, when one reads of the meteorologist, snowbound in an unpredicted storm, or sees with wonder how the robin annually beats an unfaltering 2000-mile course without chart or compass, one ponders the dubious advantages of the rational mind. An engine, they tell us, is the product of cold mathematical design reasoning, as inflexible as Newton's Laws, and it should act that way. But, to the test engineer, it sometimes appears as flighty and unpredictable as a prima donna at a public relations conference. En masse, they are even more capricious, acquiring individualistic qualities that challenge the best efforts of the inspector, as though in a deliberate effort to disprove the assumed equality of mass production birth. Perhaps the almost human qualities of engines account for the outstanding success of that early automotive test artist -- the tune-up man, who instinctively knew where to set the spark, and