Verified answer

fuel injected? 15, carb? 12

who said 15 mpgs is bad in a 85?

15 is nice... 85 should be efi not carb... at least from the factory.

with hubs unlocked with manual trans with overdrive should be able to beat 17 on highway.

Not very good, probably about 15 MPG. It all depends on how you drive. If you moderate your speed, you'll get better mileage.