That's right, this show was brought to American TV in the 80s under the name Tranzor Z. I remember watching it again at that time but the dubbing was bad plus the show was from the early 70's and felt dated.
As for this other robot show, I'm not sure. Do you remember the color scheme of this mech? It might help in finding what the show was.
Dragun is Getter Robo and I think you might have seen one of the toys. There are a few variations on this robot. He has a mostly red color scheme and some version have the saw blades on the fists. The Shogun Warriors were the big plastic ones and although they were cool, they did differ from other toy lines. I always wanted the Mazinga Shogun when I was growing up.