OK, I should know this but I don't. I might go look at
73 parts car, the seller doesn't know if it is a 1.7 or
2.0. Before I make the 2 hour drive I would like to
be able to tell him what to look for. If I remember
correctly, on my old 73 where you pour in the oil
the engine was stamped GAxxxx, is that the mark of
2.0?? If not what should I have him look for??

-Garold

GA would be a 2L case.
also, look for the number of studs where the intake bolts onto the heads.
the 1.7 has 4 on each side, the 2L has 3 ...

Andy

The 2.0 has a square air cleaner housing while the 1.7 (I believe) has a round housing. The best way to tell is by the engine number. The 1.7s start with " W " and the (US) 2.0s start with " GA ".

spark plug holes in the tin are in different places, too.

1.7 more on top
2.0 more on sides

The heat exchangers on a 1.7/1.8 have an upward bend just before they attach to the muffler.
2.0 heat exchangers are straight in the same area.

It's very easy to see when you're checking to see if it has a side shift transmission.

The easiest way is to count the number of studs that hold the intake manifold to the heads.

The 2.0 has 3 studs and all others have 4.

To quickly differentiate between 1.8 and 1.7, look for the type of injection: L-jet (1.8) uses a big pivoting flap to sense airflow and D-jet (1.7) uses a MPS sensor with bellows.

Unless, of course some PO has done something creative......

Ken