Can't say about Delo ELC, but I assume it'd be quite similar to Rotella ELC. The Rotella coolant is a NOAT coolant- essentailly an OAT like Dexcool with the addition of nitrite, which helps prevent cavitation. Nitrite is also used in most 'conventional' diesel coolant formulations (by Cummins and others) for the same purpose. Also, Dexcool is used in lots of diesel applications without nitrite- and the OAT additive package seems to do a good job of preventing cavitation without nitrite.
I've worked on trucks (including those Dodges) and heavy equipement for years, and rarely see any problem nowadays with ELC of any sort. There were major problems with Dexcool in Cummins N14 engines in the late 90's, but that's been entirely resolved to my knowledge. Also, ELC doesn't seem to work so well with brass radiators. It's been at least 7 years since I worked on a Cummins in a Dodge pickup- and I don't recall whether they all had aluminum radiators, or if it was just the newer ones. Regardless, if you have an aluminum radiator, I think Rotella ELC would be a good choice. If Delo ELC is also a NOAT coolant, then I'd just as readily use it. Those B-series cummins engines rarely have cavitation problems as they don't have wet liners, so the nitrite shouldn't really be neccesary- but I don't see that it would hurt anything.
