GM can build gas engines they can't build diesels period!
On one of the Cadillac boards there is a guy who has replaced a couple of those 6.2 and 6.5 Diesels with Cadillac 472 and 500 motors. Better mileage and better performance than the Diesel. He sounds very happy with the swap.
The lowest year for horsepower and torque on those motors is a bit more horsepower and similar torque to the 379 V-6. They can get a lot stronger but are limited by a weak valve train. They don't turn much past 4500 without serious investment.
If I were I Diesel guy I might go with the current GM Diesel. Everyone I know who has a Duramax is pretty happy with it.
