Well, I use 1/2 tank 91 and 1/2 Nitro. 12 MPG and 10 second E.T.'s =P

 

Back in the day (late 60s and early 70s) Sunoco had Sunoco 260 which if I recall was 101 octane (leaded fuel). My 66 Pontiac ran real well on that and real crappy on regular grade gas. You have to retard the timing for anything less than 101. Ah yes the day of the carburators.

 

After 454 miles driving
13.97 gallons of fuel added

 

All highway, cruise control set at 70 MPH I have seen 36 MPG average/excess of 600 miles est. range. It depends on if you ever stop on that tank of gas, if you fill up on the turnpike and get up to speed immediately, like a pitstop you will see much higher range estimates but if you pull of an interstate and have to wait for a couple of red lights the mpg reduction is dramatic.