My Goodness Dan, I would think 2 or 3 times about running a 14 year old motor out to 6,200 revs more than once every six months. Could be floating valves, air starvation, God knows what else. Unless that motor has had a good rebuild, blueprint, etc, your buddy could be asking for trouble. I know the M103 is a rock, but why go looking for heartache.
2000 Dodge Grand Caravan SE