These Box Stock class valve springs are DJ-1055I's that have been specially treated to prolong pressure retention. The pressure loss from fatigue is about half of what is seen with untreated springs. This will allow the engine to run a higher RPM for a longer time before experiencing uncontrolled valve float, requiring spring replacement.
The springs are made in batches of thousands of springs at a time and are designed to pass tech including the new 18lb at .650" check. We have not found any that failed after dyno time, however, we do not guarantee they will all pass tech out of the box. It is always a good idea to check BEFORE tech!
These springs have a green stripe and are sold in pairs.