I am trying to set the timing on my car. I have been searching for the timing marks on my 1971 1.7 but have found none. There are two notches (on the front and back of the fan). I did find one really big blade on the fan along with all the other regular ones. The big blade appears to be at approx TDC based on the distributor. See pic. Any ideas?

If you're only seeing one "big blade", then you're not paying enough attention. There are three of those "big blades", which are the fan supports. The TDC notch should be a bit under 28 degrees to the right of one of those supports. Look again for the notch.