You should check your comp ratio while you have it apart and try and raise it to the safest level you can with the boost your using, Check the cam profile too...
I agree to check piston height while apart and cam specs. 273's are not compression challenged as late 318's and 360's. Check to see how cast pistons will hold up under the boost levels you plan to run. Had a friend with a newer Mustang that was assured that his engine would hold up. After a year or two one of the hypereutectic pistons failed catastrophically taking out the whole shortblock. I seriously doubt it will be a slug with or without a 727.