The last word on valve springs are the PSI units that are exclusively manufactured for Bob Wood.
These springs are, IN FACT, THE BEST, spring on the market today.
Fact.
They will test, on a spring tester at, or maybe even 5 lbs more, after 10,000 miles the same as when they came out of the box. That is one hellava spring that can show that!!!!!!!!!!
They also come with a Lifetime Warranty to the end purchaser.
Absolutely unheard of in this industry!!!!!!!!!!!!!!!!!
These are our go-to springs once we cross the .600" lift threshold.

Scott