My 2001 496 HO is at ~350 hours. The information I have been able to find with valve spring info has been slim. The valve springs do not have much seat pressure, 65 to 75 lbs.
I know this is not a 525 blue motor that needs top end work at 200 hours, but these motors are ran harder than any truck motor.
In the interest of longevity, I want to change springs for this next season.
What I have found from comp are two springs that will fit and have found some reference to being used in boat engines.
The 26120 beehive, [email protected] on the seat,
or the 911 single spring with damper, [email protected] on the seat.
I am also going to change out the rockers for the Scorpion marine endurance RR, SCP4014 that are designed to fit under the stock/marine valve covers and a set of DANA flow torque's.
The beehives seem like overkill on the seat pressure, but anything must be better than the weak stock ones that are in there now.
What have you done or suggest?