Hmm, let's see - a Hellcat at WOT will reach 125mph in about 11 seconds, so after 2 minutes at WOT, how fast would it be going?
Now, assuming that it needs to be at WOT to maintain its top speed, which Car & Driver says is 165, if it burned 1.5 gal/minute, it would be getting 1.8 mpg.
At 1.5 gal/min, it would empty its 19 gal tank in 12.7 minutes, a little bit more time than a Bugatti Veyron, which would empty its 26 gallon tank in only 12 minutes.
The Bugatti would be going much faster, of course, but the Hellcat is only 2.5% of the Veyron's price.
EDIT: It's been pointed out that 165 is way too low - reachabel by mere R/Ts, with the limiter defeated. Let's still be conservative and call it 195.
So, at 195, if it burns 1.5 gal/minute, that's 2.2 mpg. You'll still empty your tank in 12.7 minutes, but instead of doing it in 34 miles, you'll do it in 41 miles - while going early 200 mph.