Chevrolet Repair: Distributor gear, small block chevy, glutten for punishment

Question
I have a small block chevy that was rebuilt about 15,000 miles ago, and was running fine.  I wanted a little more out of the engine so, changed the cam and now it eats distributor gears.
Details:
The new cam and lifters were changed about 3 months ago.  I kept the same distributor, intake, and rockers.  I did change the timing cears and chain.  It is a mild hydrulic flat tappet cam with 240 duritation and 480 lift.  For 2 months it ran great.  One day is started missing like crazy.  Investigating it, I found the distributor gear was starting to strip.  So, I replaced it.  The car ran good for about a week and the same thing happened.  Being a glutten for punishment, and not knowing what else to do, I put another gear in it.  This one lasted about 20 miles.

Answer
EMMM!? Did you prelube gear before install, have you taken all free play(up&down) out of distributor, what is the oil pressure? Did the dist. fall in place easily, or needed a push down to engage oil pump drive? And...guess where all the shreaded metal is at? Let me know, and we'll go from there!