If you are hearing engines turning harder than yours will turn, this is PART of your solution. This is a true STOCK valve spring that has been tensioned to 10.8 lbs at .850". It meets all Box Stock rules at this time and will outperform any other spring on the market that will pass tech. The "Trick" is not just making springs start out at max pressure, but pre-stressing them so they settle at 10.8 lbs and stay there for more than just a few races. ARC has made more of these springs than anyone and they have it down to a science. The springs are each produced with a Intercomp Digital Spring Pressure Tester that has been specially configured to insure repeatable accuracy beyond what a standard commercial tester can achieve, then they are verified on a CERTIFIED 10.8 lb spring tech tool sold by BSP as the official spring tech tool.  Our goal is to give you the best performing, longest lasting springs that will pass tech.  Contains 2 springs.