I'm a brand new old guy here. This is my first post. I have a 1986 2.0 Mighty Max. My Dad bought it new. It became mine when he passed away. It has been in and out of storage over the years since. I recently resurrected it and have done quite a few things to make it reliable and run unbelievably better.
1. Sent head to Ram Cylinder. They overhauled the head and plugged the jet valve B.S. I plugged the EGR port. I removed all the original wiring and hoses and associated with the unworkable smog black magic B.S. New timing belts and confirmed correct balance shaft timing.
2. Installed the Weber carb kit with K/N filter. Converted to electric fuel pump with 3 PSI regulator.
3. Bought the tuned header from the guy in Australia.
4. All new ignition - rotor, distributor cap, coil, wires, plugs. Advanced timing slightly.
5. Flushed and repaired leaking radiator. New water pump.
6. Installed oil cooler.
7. Switched to synthetic oil in engine, transmission, steering gear box and rear end. Added generous MotorKote treatment to all four.
8. New original size radial tires and shocks.
9. Cleaned up nasty air ducts and evaporator for A/C and heater. Repaired leak in A/C hose & recharged A/C.
10. Repainted fading tops of truck and inside bed with Imron silver.
11. Tinted windows.
12. Electric tach.
13. Lots of other little TLC stuff ... head liner, seat covers , etc.

Now to the improved gas mileage and power. With the old carb and leaky jet valves and the smoking and knocking I was getting about 18 MPG in town and maybe 21 MPG on the highway. I had to down shift any time I went up a hill and could not accelerate till going down the back side.
I checked the interwebs and when new the spec.'s for this vehicle was 21 town/24 highway. That was with pure gasoline, not this whiskey laced crap we have today.
I just took it on its first real highway trip just to see what improvements I had made. I drove from North Texas to Galveston on the interstate keeping it as close to 60 MPH as possible without getting run over by the mostly 80 MPH crowd. I was facing a strong headwind and ran the A/C about half the time. I was thrilled to find out that I got 30.4 MPG for the trip down. Same conditions coming home, including a headwind, but not as strong. I got 30.1 for the return. Prior to highway trip I had been getting combo mileage on shorter trips from 26 to 28 MPG.

Engine runs unbelievably smoother and with LOTS more power. It will accelerate up those same hills now in 5th gear. It sounds good and is a kick to drive. Reminds me a little bit of the Porsche 914 I had as a young 2nd. LT back in 1973 with the sound and acceleration. It does not corner near as well though. My German Shepard fills the passenger seat and won't let me leave the house without him. I can hear my Dad laughing every time we drive it.