I see in a post from 2007: http://www.opelgt.com/forums/6a-engine-mechanical/8812-opel-springs-big-valve-head.html That RallyBob commented: FYI, stock spring installed heights on a 1973 1.9 engine are: Intake: 1.57" - 93 lbs Exhaust: 1.36" - 97 lbs Can anyone tell me what the installed spring...