I used to work at Chrysler - Jeep Truck Engineering in the Dyno Labs. We ran the same harnesses for both engines. We would swap out the ECU's and tie off the 1 and 2 injector and C-O-P connectors. Voila! Both engines, one harness. Use the 4.7L HO engine. 310hp out of the box.
K&J Auto Service in Hazel Park, MI used to be able to reprogram JTEC's. Today though, Arrington Performance in Brighton, MI has the capability.