Thats odd, mine did not come out that stiff after they were installed. I have 165 on the seatSo I took a spring off these heads and also took a k800 to my neighbors friends head shop. The promaxx springs are supposed to be 145 seat pressure and they were 134 ish! The k800 springs were 195!! He thought those were too heavy for my lifters and I tend to agree so I’m gonna look for around 150-155.