Cam wiped out, what the hell did I do wrong?!?!?

So any suggestions on a new cam and cam bearings? Can the bearings be changed without pulling the engine? I think probably not, but I'm tired of R&Ring engines in this thing.
If I were you,I,d get ahold of Brian at IMM engines(Cali.)He should be able to give you answers to all your questions and help get you back together.Ask about a roller cam.Mine is .631 lift @.050 252@258 @106