The only frame of reference I have for gas mileage is in eBay. All these folks selling pintos that get 25-35 mpg. I am not even close to that. My 2.3 bob gets 20. I don't know highway mpg as I don't go anywhere. Tell us your honest mileage. Not just for the 2.3 but for all four stock engines. I am sure others would like to know. Any ideas that have worked to improve mileage would be appreciated. 

My 73 wagon with 2.0L 4cyl and C4 auto trans is getting about 23 MPG in city and about 28 MPG on the freeway. My 78 Sedan with 2.3L 4cyl and stock 4spd trans is getting 25-28 MPG in town (depending on how hard I drive it), and 33-35 MPG on the freeway.

My 73 is completely stock with everything connected appropriately.

My 78 has the EGR removed and blocked off, with the distributor connected directly to the primary vacuum source and not the carb where it is supposedly supposed to be connected. I also have the motor bored .020 over (thus slightly over sized pistons), but everything else is stock aside from the cam which I swapped out for a stock 91 mustang roller cam. Timing is advanced slightly and I have it tuned toward the lean side with no ill effects to drivability or acceleration.

I get 25 with a 5 speed, 94 2.3, 2500 carb. with headers in a 73.  Fred   

Ha!   My ugly 73 beater Pinto has a 1600 stick shift.  It gets 33 mpg at 70 and 40 mpg at 55.
I drive it 110 miles a day through Detroit, even in winter.  That is why the rust is starting to take hold.
I will probably take it to the Ohio event even though it is not much to look at.  But the engine looks good! 
 
Here is what I did to get that great gas mileage:
1.  I changed to 15" rims & tires and it gives me 10% overdrive.  (Before I has even taller tires for 20% overdrive, but they would rub)  I verified my speed and overdrive by using an online calculator and my Garmin GPS.
2.  I added an electric radiator fan and removed the mechanical fan.  The electric fan only comes on when caught at a dead stop for more than 5 minutes. 
3.  I added a Mallory 4758101 electronic distributor.  It has a better advance curve besides the better spark.
4.  I use Bosch 4016 platinum plugs.  Make sure to torque them as the box says.  Over torque and they run bad!
5.  Mobil 1 oil
6.  I rejetted my carburetor.  (actually had to jet it richer)
7. I added a front and rear spoiler for less drag.
8. I got rid of any junk that added weight  (no charcoal recirculation system, no spare tire, etc)
9. I smoothed the inside of the exhaust manifold and added a turbo muffler.

Keep in mind that my engine is a 1600.   
Wifey has a 1979 2300 that I will reseal the engine over the winter and do some modifications.  So either later this winter or next spring I will see what mileage we can squeeze out of a 2300 with an automatic.   

Cruising back from Carlisle at 65-70 the Ol' Mail Wagon gave
back 33.6 mpg.  This car gets better mileage when I run It hard.
It likes 3000-3500 rpm.  Its just the way I have 'things' set up.
 Hope to see old friends  9/11 in Macedonia !!
 
                    Later-----Dick

My car got somewhere around 28 mpg  +/- 10% when I was coming back from Carlisle. The speedo is about 7-10mph off so the exact mileage is not known. Either way it is better than my v6 Chevy Malibu Maxx. It just depends what kind of condition the car is in. My car has had the engine & fuel system gone over so it's pretty much in tune considering its age.

This message thread got me interested in my mileage again.
As I drive over 100 miles a day to & from work I always track my mileage and have the opportunity to experiment and get good data. 
 
Up to now I have used the stock air filter housing system that pre-heats the air to eliminate carburetor icing in the winter time.  I kept that in place because I winter drive this car and the 1600 has unusual mounting.   (fire arrestor, brackets, and a carb vent)  No aftermarket fits.   
 
Last week I took another air filter lid that i had (it has the snap on plastic lid) and cut some holes in the top to get cooler air.   My mileage is now 35mpg at 70mph and 42mpg at 55mph.   And this even though some hot air from the preheat can still.    Next I tried to make more holes and it broke.     So I put the stock air cleaner cover back on.
 
It should even get better if I plumbed an air cleaner to get cooler air ahead of the radiator and eliminate the pre-heat.
 
I will start searching for a complete 1600 air cleaner assembly to modify.  I could use it until Halloween and next spring.