Tim, you could just have a bad oil cooler.  This is the unit that is located
between your oil filter and the flange (see the two coolant lines hooked to
it).  This unit is $150 (alot cheaper than a new head).  Let me know if I can
help you out with this problem.

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16

New Phone (856)-327-4936
Shop: (856)-765-1583
Fax:     (856)-327-2242