The DT466 is a sleeved engine...meaning that it can be rebuilt at a cheaper cost (when the time comes)
Both are 6-cyl units.....both are good products
The DT466 has been around for a while
You can't discount the Cat is the standard in the industry....
IMHO, the CAT matches better to an Allison 1000 or 200 series trans while the DT466 seems to perform on the series 3000 Allisons..
I think it's in the torque at certain RPM ranges.
Frank in Pa.
"The Beast in the East"