Super Six fuel mileage

Its funny this post is here because thats exactly what I came on here to look for. I have a 69 valiant 4 door 225 with single barrel automatic no clue what it has for a rearend. At any rate this car had sat for almost 4 years before I got it and started driving it about 2 months ago. I have wondered about the gas mileage and just today got to figure it out for the second time....combination rural/intown/highway I got just shy of 26 mpg. I have got these results both times. Stock motor with the same plugs wires it had on it when I got it....im going to do it one more time filled it up today it just doest seem right but the numbers dont lie??