[95GTS]

What kind of gas mileage could one expect, roughly, from a stock 289 in a 66 Mustang? Assuming the car is 100% stock. I'm kinda, sorta, looking at one and don't know much about it yet. I'm needing something with at least around 20 mpg/tank. I don't know what tranny it has, though, or rear gearing. It's a hardtop/vinyl top. No vert.