Check these guys out:

http://www.samstagsales.com/

or these guys,

http://www.baumtools.com/english/index.cfm

or this guy,

http://rusty.mbz.org/

I'm anticipating head job on my 603 so I've been studying up! Good Luck!

p. S. How about a compression tester adapter? It will have the same threads as an injector and a threaded hole centered in the top. Like this one?

http://tooldesk.com/cgi-bin/webplus.exe?script=/shop/item.wml&groupid=Compression&prodid=ATD%2D5562&deptid=Diagnostics%2FTesting&SessionID=2002129215432457