Valve Spring

Free Length (Approximately) 46 mm (1.811 inch)
Spring Tension (Valve Closed) 246 - 270 N @ 38.0 mm (55 - 60 lbs. @ 1.496 inch)
Spring Tension (Valve open) 549 - 611 N @ 29.3 mm (123 - 137 lbs. @ 1.53 inch)