valve float
 

Just wondering the symptoms of valve float and how long should the prc 660's last. They have like 10-12 k on them.

If you have over .600" lift with that much mileage is get there seat pressure checked....a good performance shop can check them quick on the car and should only charge an hour or two labor

Valve float feels like multi-cylinder high-speed misfiring coupled with some powerloss, almost like hitting the rev limiter.