Replacing vent window seal how hard?
 

I need to replace the vent window seal in a 74 targa the rubber part,
Anybody know how hard this is to do?

Not hard but tedious. You must remove the whole window frame and then the opener mechanism, insert rubber and reassemble. If your rubber stops are shot you should take advantage and take the whole frame apart to rivet new ones in. Mark frame height and alignment before removing.