if yoy use hpyer alloy pistons and did not have the rigth end gap to much cr to timming. to lean hot spot on the pistons hot spot on the head camber . there are many things . nos will burn down piston to .you mite be ok hone the bore out and putting a new piston in BUT you need to fine out what made the piston go away the crank mite be ok BUT i would take it all down and look it all over good