CB Performance has introduced these new top of the line valve springs. These dual springs were designed for up to 8500rpm. The VW650 valve springs drop-in to heads machined for VW diameter dual springs. The VW650 springs are designed for extreme endurance so we use a Nascar grade proprietary material that has unsurpassed high cycle fatigue life. These springs have extensive surface finishing including nitriding, polishing, heat set, and a micro shot peen. For the strip or street, the VW650 valve spring will hold up to the most demanding driver. Installed height of 1.540" gives you @ 160 lbs. of seat pressure, and @ .630'' lift you have an open load of 420 lbs. With the VW650 valve springs you can run up to .630 lift, if your heads are properly set up!