1.640 NexTek Dual Valve Springs Valve Spring - NexTek - Dual Spring - 647 lb/in Spring Rate - 1.070 in Coil Bind - 1.640 in OD - Polished - Set of 16

1.530 NexTek Dual Valve Springs Valve Spring - NexTek - Dual Spring / Damper - 435 lb/in Spring Rate - 1.170 in Coil Bind - 1.530 in OD - Set of 16

1.550 NexTek Dual Valve Springs Valve Spring - NexTek - Super Finish - Dual Spring - 618 lb/in Spring Rate - 1.150 in Coil Bind - 1.550 in OD - Set of 16

1.650 NexTek Dual Valve Springs Valve Spring - NexTek - Dual Spring - 635 lb/in Spring Rate - 1.105 in Coil Bind - 1.650 in OD - Set of 16

1.311 NexTek Dual Valve Springs Valve Spring - NexTek - Beehive Spring - 353 lb/in Spring Rate - 1.100 in Coil Bind - 1.311 in OD - Polished - Set of 16

1.500 NexTek Dual Valve Springs Valve Spring - NexTek - Dual Spring - 800 lb/in Spring Rate - 1.130 in Coil Bind - 1.500 in OD - Set of 16