Remember you're comparing a 100HP slant six to a 300HP (gross) 360...and they get the same mileage!
I'd say that's a fair advancement.
My 03 Intruder 800 got 45 MPG no matter how I drove it.
The 98 1400 got 38 if I babied it and 30 if I hammered it.
I rented a brand new 03 F150 crew cab 4x4 with the 5.3.
Got 17 MPG hwy towong a 4000# trailer. Thought that was pretty good.
