Hello,
This is my first post. My grandma owns a 79 caprice classic with a 250 inline 6 and will be passing it down to me soon as she is getting another car.
The problem with the car is that it has really really poor gas mileage, about 10 MPG in careful city driving. The car has an automatic transmission which works fine, A/C(currently not working), and power steering. I dont know the vin or have any information as to the rear gears. The car has a new carb which was installed about 6 months ago(dont know what carb it is but can look into that). I took off the spark plugs and they had oil on them so i guess the piston rings need to be changed. The car does not have much power, it barely gets to the top of a steep hill and in reverse it wont go uphill at all. I know its a heavy car but i feel the power it has is too little for a 250 cid. What mods or repairs do you think i need to do to get some power out of it and maybe get around 20 MPG city driving or at least close to 20?

Thanks for any help provided, i cant get much information here in El Salvador since everybody owns a japanese car here.