Yeti, I looked the CJ up in the John Muir book. Going by this the '75 2.0l was prefixed GD.
It is not too clear, but it looks lile in the US mid seventies:
Cx n = 1.7
Ax n = 1.8
Gx n = 2.0l
However my 2.0l is prefixed CU, small valves and concave piston tops. (Is that like yours?)
My bigger valved 1.8l T412 is prefixed AN so that follows.
I'm happy for you that your T4
is bigger than your T1
Matt