When I bought my E-350 in 99 (7.3) I remembered being told how to break in it. Then, I came across this link which reinforced my concern:
Cummins' Break-in Recomendations - TDR Roundtable
Either way, the wife walked out with a 2008 F-250, 6.4, with 13.1 miles. She's in heaven.... As for my van, I'm still in love with it, lol.