13" or 14" wheel on Civic - MPGs?

I am looking at
http://www.fueleconomy.gov/feg/bymodel/1994_Honda_Civic.shtml but I can't
tell why some Civic 1.5L 5spd get better MPG than other lsited Civic 1.5L
5spd for the same year. Could it be because of 13" on the DX & 14" wheel on
the LX? The MPG ratings are 42/46, 40/45, 34/40. What trim line of 1994
Civic 5 speed gets the best MPG with a 1.5L 5 Speed? I assume this mileage
will decline when the car is over 150,000 miles?

 

There were a number of different engines used in the Civic that year:

D15B8: 70 HP, 1.5l 8 valve engine used in the CX hatchback
D15Z1: 92 HP, 1.5l 16 valve VTEC-e used in the VX hatchback
D16Z6: 125 HP, 1.6l 16 valve VTEC engine used in the Si hatchback, the
EX sedan and the EX Coupe
D15B7: 102 HP 1.5l 16 valve engine used in all other varieties.

The VX with the D15Z1 engine was the most fuel efficient one, rated at
47 / 56 city / highway. It had the fuel efficient engine, lighter alloy
rims etc.

The CX was rated 42 / 46 and the DX hatch manual was rated 34/40

 

Any idea what the mpg rating was for the 1.6L (106 hp)engine in the 98 civic
dx? Thanks.

 

You can find that info on http://www.edmunds.com. The rating was the
same for the DX Coupe, hatch and sedan, 32/37 with manual, 29/36
automatic.

 

I ended up buying a 1994 Civic LX 1.5L 16valve 4 door tonight - 176,000
miles for $150.
needs head gasket and much body work, etc.

How close can I expect to be to DX hatch manual was rated 34/40

Should I just have the head tanked and reinstall if it passes a leak test or
can I improve on the mileage with new technology by replacing the head?