Well, if motorcycles counted I would already be there! My largest and most powerful motorcycle, the SV650SF has a best tank of 83.9 MPG. My carbureted grey import bikes struggle to break 60 MPG.
The V6 accord on the other hand is a LONG way from 70 MPG. Best tank of 46.0, best trip of 52.0. I still have plenty of mods on the table, but I don't think it would be capable without going
ALL OUT BABY!
I took it to the 1/4 mile dragstrip recently and got a best time of 14.695 at 92.16 mph. Of course my clutch was acting up so the 4th gear shift took way too long. Probably could have ran a 14.5 at 97 mph with everything working. And this is with skinny little 205 width low rolling resistance tires.
On the subject of the dragstrip, i'm fixing up my grandpa's 1983 Honda V65 Magna. He wants to see me get it into the 10's. I'm no peewee gleason!