Manley NexTek Series 1.580 OD .832 ID .730 Lift Oval Track and Endurance Valve Springs Cigarette pack cut out hi res stock photography and images Alamy. From drag strips to short track and endurance circuits, the Manley NexTek series is engineered for serious racers. NexTek springs resist pressure loss and valve train degradation even in the most demanding race conditions. That means more consistent spring force deep into a run, reduced valve bounce, and improved overall stability for high RPM performance. Built to outperform and outlast in real world competition. Specially processed premium grade chrome silicon that is virtually free of impurities or surface irregularities Tested by leading engine builders and are confirmed to be the best performing valve springs on the market today No degradation of spring pressure in the later stages of a race