Stock springs are 50Lbs installed, these are 70Lbs so up 20Lbs or if you like, a 40% increase.
Fitted at the stock height the max valve lift is 12.9mm. If you need more tension then a .060 shim brings the seated pressure up to 85Lbs (71% increase over stock) but drops the available max valve lift back to 12mm.
16 units to a set.
Let me know if there’s anything else you need.
Performance Valve Springs
Not sure what the benefit of these boils down to with regards to HP, but it’s intriguing anyhow.