2019 comes in v8 5.6L 400hp and v6 4.0L 275hp.
The older 2010-2015 models come in two v8 options both 5.6L but one with 320Hp and 400hp.
Basically on such a heavy vehicle the fuel consumption on a v6 is very much similar to the v8. In certain occasions I found that the v8 consumes less!
It depends how you drive the vehicle and at what speeds, can vary pretty much between city and highway.
The best I got on highway and on speeds less than 120 (around 110) was 14L/100km, but this if you reset the meter while driving on the highway.
Combined city+highway: i never got anything better than 19-20L/100km.
Sometime it goes up to 22L/100km.
If you drive it un city alone, then you need a petrol station connected behind you.