LOL, My corvette had one of those "instant economy" digital gauges and when I put the peddle to the floor it went down to 3MPG! It had a 20Gal tank... So I'd get 60 Miles on a full tank!
Probably less... By the time I'd get to the top speed (MAYBE 150) that number would go down to 1MPG if that.
I got the car up to 145 once... But the suspension just wasn't good enough back then for me to keep it there.