Lash Caps....Seven Came Off

First time with an engine with lash caps. 360/408 hydraulic roller. This is an engine that was built by Mike at at MRL Performance. He broke the engine in and tuned it on his dyno. The engine sat on my stand for maybe less than a year. I occasionally primed it, turning it 90 degrees at a time. After putting it in, it was primed thoroughly. It started right up, missing and rattling bad from the top end. Pulled valve covers and found some. Pulled intake and found the rest. This is going in a street/strip car, shifting about 6500. It makes 543 hp and close to the same tq. What happened here, and now i'm paranoid about this engine now. Any advice appreciated!