If you follow the ITCS rules explicitely, you can only run stock cam timing. You are allowed to use an offset key to move the timing back to stock after you mill the head.
If the 2.3 is similar to the 2.0, then the optimum cam timing is around 3 degrees retarded.
71 ITB Capri (projected '03 SCCA ITB SF region)
73 PS3 Capri (Enduro racer)
77 GTI Cup Wabbit (my rain car)