Paul U. pictures piping water rather than air through the Porsche's heat
exchangers, presumably after doing lots of work to make them watertight.
Probably less trouble, and cheaper, to use some big GM V6 as the donor:
3.8 liter GM V6 estimated price: $2000.  3.6 liter Porsche flat 6
estimated price: $9000.  I *still* think air for air, water for water is
a good rule.
B.