The compression ring land and ring on all 6 pistons of our Performance
Engines Cont. IO-550 failed before the 40 hours were flown off.  It is a
bitter pill to swallow but a full tear down inspection is necessary.
Barrett Performance Engines did our inspection after we replaced our pistons
with stock ECI pistons/rings and luckily did not find anything else.  We now
average 15 hours per quart.

Steve Colwell  Legacy 450 hours