I just finished re-building 3.2SS with new cams and refurbished rockers. I ran engine 20 mins at 2000 rpm on mineral straight 30 and then changed to M1 5-50 (A40). Then took it for a drive an hour and removed valve covers to check. There I found #6 exhaust side rocker arm damaged and also corresponding cam lobe. All others were fine. As a part of the post mortem I checked flow pattern from oil splash tubes and all nozzles are spraying as they should. What may have caused this; 1) a problem with the cam or 2) a problem with the rocker arm ? Or can there be any other reasons ?
As a note the same happened on previous rebuild except it was #4 inlet. Same cam supplier but new OEM rockers
What to do on my next attempt ? 
