Ok this is on a 01ECSB chevy that we built a few years back, its got a custom fit rear mount on it running 12lbs. The cam is around the 216 and .550 lift, 918 springs, hardened push rods, all the normal stuff. He had his oil changed yesterday and they found needle bearings on the drian plug, so he called and I had it dropped off. Well we pulled the the covers off and sure enough number 5 intake rocker and number 7 exhaust rocker were missing the caps on the sides. What would cause this? Also has anyone ever heard of this happening?