The DD 15 engines were released before SCR. The Cascadia was built a few inches taller than Columbias to accomodated the One Box. It was a phase in, gradual. On a side note, the truck I drive doesn't have any parameters set, so I don't have to worry about being crippled by a pencil pusher trying to.squeeze a bit more economy from it. The 10 speed is adequate for what I do. That 18 or 17 hundred Rev limit wouldn't hurt it as much as an early 60 series, but I can run it uphill delaying up shifts and skip shift quickly going downhill.
I have driven for a great many years 37 to be accurate. the series 60 is nearly bullet proof. all the power of CAT. the simplicity of a CUMMINS BIG CAM. and decent mileage to boot - weight in 79.900 at 75 mph get around 6mpg depending on terrain. with pull power left to spare at 1700rpm with a 13 speed and 379 ext hood are my proven weapons of choice.
Not sure how this has much relevance? I've had a 12.7 at 2800 rpm. I'll take that in a 12.7 over a 13 or 15 DD. I've heard this.
I know in 14 there were 3 different engine builds for a dd15. Who knows how many different kits there are.