Take a closer look at the motor. Not all VMAX motors are fuel injected. Mine (2003) is a carb motor. They also made the OX66 (fuel injected) and the HPDI (Direct Injected).
3 different technologies. Of the 3, the HPDI is the most fuel efficient, with the OX66 second and carb third.
At WOT, they all burn about the same amount of fuel, but at mid and low range is where the fuel injected and direct injected shine. The added advantage of fuel or direct injected is startability. A carb motor is harder to start, where the other two should pop off instantly if kept tuned.
As mentioned, the FI and DI motors will use less oil.
The flip side to all of this is the carb motors are pretty much bullet-proof and cheaper to work on.
Glenn