I'm Cummins swapping a '74 Duster, thought I'd share the progress.
I participated in the 2010 X-Prize 100 MPGe Fuel Economy Race (Liberty Motors #20). One of the entrants had a Mustang with a Detroit diesel that got 138 MPG and would pull 10's in the quarter. It was featured in Hot Rod Magazine around that time as well. I say Go For It!