The Magnum heads are lift limited, sticks in my head that 0.512" lift is at the edge of what a Magnum head can take. Did you swap out the springs and such? I know you have run it, but could be a failure point later on if it is an issue.
yes i did swap the springs, i went with magnum spring uprgrade kit from Hughes Engines and did rotation checks before i fired the engine. but yes, it is in the back of my mind.