I had a stock rocker spill its guts into the motor. There are 33 needle bearings per side of each rocker arm. I only found 29 so I had to pull the motor and tear it apart to find the other 4. I then made the switch to Comp Cams Pro Magnums rockers. Full roller, adjustable with guideplates and have performed flawlessly on the street, track, autox, trackday etc......I wouldn't ever put a stock rocker back on, unless it had the aftermarket conversion done. I feel your pain pulling the motor to find all the pieces....been there done that.
Stock LS1 parts FTMFL tooooooo
http://www.cardomain.com/ride/2446297/2
Chris