Last year before and for the first few months of modding my car I made a 630 mile round trip to visit relatives. I was getting 43-46 MPG with my mods (no boat tail) and was wishing to be able to hit 50 MPG on the highway part of the trip. The trip is split 50/50 highway (55 MPH max) and freeway (55 MPH min). I was also wishing that I could do the whole trip in one tank of gas. From my math I needed to get an average of 49MPG to make it. That would be getting back home on fumes only.
This weekend I make the 630 mile round trip on one tank of gas
and the SG reads that I have 1.1 Gal left. I will fill up on the way to work tomorrow and see what my trip average was.
The week of commuting before my trip was a record tank at 53.xx MPG!