milling my 906's heads .080

Years ago i bought a set of 452's that were opened up to max wedge port size and ported heavy by Dan Davork out of Waldo Fl. He also cut the heads .050. I ran these on a 440 with zero deck Wiesco pistons. I can tell you this, to me the heads looked and felt like they were fragile. They worked very well and made a lot of power. But later on they did crack around one of the head bolts on the upper row of short bolts. Was it due to the heads being cut .050? or the fact they were ported so much? I really don't know for sure. Just giving you something to consider.