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A Buxton billet spring compressor measures the valvespring pressure. Our Comp valvesprings showed 425 lbs. on the seat and 1,100 lbs. open. To put that into perspective, the typical mild street hydraulic roller is 140 lbs. on the seat and 350 lbs. open. The heavy springs are needed to control the valvetrain at 8,800 rpm. Pettis also accurately checks coil-bind height, which can be more important than actual pressures. Thanks to Spintron testing, the racing community now knows that it is typically better to set the springs closer to coil-bind. The old belief to set them further away has shown spring surge and vibration issues at higher rpm levels. These springs were set up 0.060-inch from coil-bind.