Stu, well I use std RS turbo valve springs and a cam with 12.6mm lift, have no problems reving to 7500. I have had the odd rocker pull off in the past, but not since I torque the rocker down at 28ft/lbs. Basicly at that torque if the tread is damaged it will pull the rocker stud out, meaning a repair is required rather than running it and it comes out at a later date.

Never had a snapped rocker!

I repair with a keenserts.