Cylinder head torque setting 4.0l

Hi all car blew its head gasket on the way to birmingham nec last saturday can anybody tell me the torque settings do I need to replace the heads after it as been torqued down do you run it for 25mins and let it cool and retighten or do I do 500 miles and then retorque it your help most appreciated

According to RAVE tighten all to 15lbs ft (20Nm) then turn a further 90 degrees then another 90 degrees. Do not do 180 degrees in one go. You will need to buy new bolts as yours will have expanded