I would have the heads pressure tested and a valve job done by a local
machine shop (if you are reusing old heads).  Also this is a great time to
replace your water pump.  I would also be sure that your engine gasket kit
comes with the yellow head nut sealant (included in my kits) and if not get
some of this for the head nuts.  If the heads are pitted you can either have
them welded, or try to fix with JB Weld.  If they fail the pressure test then
I would recommend getting new heads (I have these for $395 each).  Hope this
helps.

Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: (856)-765-1583
Fax: (856)-327-2242