well for arp's you can get them off ebay for bout $80
and head gaskets there are quite a few... hks, cometic, greddy... prices vary...
a few supra websites you can have a look at....
www.suprasport.com
www.mvpmotorsports.com
www.horsepowerfreaks.com
ring your local reconditioners and get quotes for checking the flatness of your head and skim and checking your block.. just make sure they're not backyard reconditioners hehe