Engineers with tools like these can stabilize a valve train, but these engines, unlike the V&H, are for sale (yours for $42,500). That means the teams modify them to stay competitive. As ETs shrink and terminal speeds swell, engines work harder. Until recently an S&S engine was doing well to make four runs without needing maintenance (like the Suzukis of a few years ago, getting maybe five runs from a crank). Therefore they applied to NHRA to be allowed a basic redesign. NHRA, feeling they’ve achieved engine parity in PSM, regard redesign as “potentially destabilizing”—as when V&H were allowed to run four-valve heads, winning 15 of that year’s 16 events. To meet this objection, S&S pitched this redesign as a reliability upgrade, which it certainly is. Otherwise it would have updated the wedge-chambered squish cylinder head as well, using the latest airflow techniques. Next time!