First of all, the best way to identify your Subaru is to have a look at the VIN plate. It is the shiny alluminium plate riveted to a panel inside your engine bay.
It looks like this

Now the what you are looking for is a string of letters that starts with either JF1, JF2 or JF3
After this will be 2 letters, these tell us the chassis code for each model
For the 1980-1984 models normally known as the 'MY Series', 'Leone' or simply '1800'
AB sedan

AF hatch

AM wagon

AT Ute (up till and including 1984)
AU Ute (After 1984
AW coupe

These came with a 1600cc or 1800cc pushrod engine known as the EA71 or EA81 that look like this

Usually identified by the distributor at the front of the engine and a blue "kidney bean" shaped air cleaner.
These were coupled to either a 4sp manual or 3sp auto transmission, both in either FWD or 4WD, with wagons and utes having the option of dual range.
This will get updated regularly with more information on other models