I wouldn't use them---mostly we use Dart and also some afr heads--they been in the racing and head business for years(ever since the rules were changed to where you didn't have to use a factory head)(in fact, Dart and AFR are probably the reasons the rules got changed)
These guys have been in racing from day 1 and all the BS has been engineered out of there product---It isn't done because of cheaper imported castings, a random cnc machine or the offshoot of a family business that manufactures something else---