With a 750 lift roller and a 2.40 intake valve shifting at 7500. How often or how many runs do u get from Manley springs w 750 open pressure

I will only run 1 season a normal season for me is 125 passes. Then onto new springs and locks. You can go longer some say 250 passes but when things go wrong in the valve train department it makes for a very bad day. Are these titanium valves?

I actually had a discussion with a manley rep today about valve fatigue. And it is determined that the faster lobe rate such as a roller will increase fatigue, the higher the heat then quick cooling adds to the fatigue failure. however the number one cause was useing a underated spring for the cam application. however a oversized spring can cause valve fatigue ( broken stim ) ouch. well they are racing motors.