How to rebuild an engine for better MPG?

I'm gonna rebuild an 83 Lincoln Mark VI, now I know what most people think about Ford but I got it because I had one when I was in high school. People like Cadillac I like Lincoln. It runs good but its been sitting for 2 years in a barn, so before I start buying parts for the engine. Is there a way to rebuild the engine for better MPG?

No matter what you do that thing is going to use a lot of gas. Outside of keeping cars tuned up and the tires properly inflated there's no magic add ons that will increase MPG significantly. What you have is what you are going to get what it comes to millage.

There's probably the TBI 302 in that. You're not going to get particularly good fuel economy out of this car. You're going to looking at around 14-15 MPG city and 19-20 MPG highway, and that's with a freshly rebuilt (to stock specs) engine. You're not going to find much in way of fuel-economy enhancing aftermarket parts, but there are plenty of performance enhancing options. Going to a taller (numerically lower) rear end won't help because this car already has a 3.08 or 2.73 (or there abouts) axle ratio.

If you are concerned about fuel economy, then you should probably be looking at other vehicles.