First and formost, the size is issue. I talked to Cummins and, as expected, sales/customer service has zero information on the Repower package. They will have nothing until the day after the official release is made, if that soon. Can't get any dimensioned drawings. Am assuming it will be close to the ISF 2.8, but no guarantee, and haven't been able to find any drawings that reference dimensions from the crank center line on that one either. Companies have to understand that information is necessary up front.
The COE is so much more space restrictive than the conventional cab, I've already eliminated many gas engines from the possible list for being too wide. The taper in the front of the frame is a problem in all trucks, but the height is very critical in the COE.
A tall diesel could turn the cab into a 2 seater unless the motormount/pan area is narrow enough to drop through the frame.