Good you found the issue..sucks you gotta tear it apart.
Glad you found the problem and that the damage wasn't too bad. My machinist told me to use loc-tite blue on the cam bolts. While you are in the engine, are you putting in better pistons?
Update: My builder did a leakdown test and found no leakage - no bent valves! He also filled the intake ports with fluid and flipped it over and filled the exhaust ports. Again, no leakage. Should get it back this weekend!!