This quote sums up Zeus, and my feelings, well.

From my time researching Zeus I would agree that it is likely a late 60s frame. Much more documentation post 1973 and this frame does not match anything I have seen in my post Zeus 2000 introduction research.

Two things I have learned to watch for in Zeus frame identification, 1/2 chromed seat stays/forks and inlayed dots/triangles on the head tube lugs and forks.

I wouldn't rule out this being a competition model around 1970. Most likely, you'll come close but never know! Such is a life with an older Zeus!

Love my 1973 2000, it is in light blue and I wonder what shade of blue your frame was originally. It appears lighter near RD.