I have owned many of these, and yes, its a common issue. im sending along a link to a discussion about this subject, and I will post up here (copy and paste) what someone wrote thats pretty worthy. Good luck !
www.dieselplace.com
"Check for cracks on both heads but they are common to crack between the valves. I have reused those heads with cracks between the valve area and never had any issue.It would not hurt to have the cylinder head mating surface machined just a little.Maybe .005" or so which is'nt much.Check your block as well on the deck area.A removal of .005" there wouldn't be a bad idea either.Ive had both of my olds engines machined on the deck area.Having .004-.007 removed with no issue.You just need to use the .010 thicker victor reinz head gasket."