how many runs on the springs to get them to lose 20lbs seat pressure?

new, those springs are closer to 250-260lbs @ 1.900.

for now i'll only add that sometimes certain spring and cam profiles just arent happy with each other. my guess is, your valvetrain is going into spring surge and thats whats causing the breakage.

i would up the pressures, and switch to a different spring.....maybe something with a damper.

do you have the cam lobe numbers??