If I knew how to do the math to convert to MPG(miles per gallon) I might be able to help you fugue it out.
Otherwize,with a built Lightning motor at 594 RWHP in my 6000 pound truck, I get about 14.5 to 15 miles per gallon on the highway.
A stock Lightning should do a lot better then that.
I think I'm pay about $410. to $420. a gallon for 93 octane fuel here in the USA.