I am looking to upgrade my tires and wheels and go as wide as possible, does anyone know how wide a 77' 280z can handle?

 

I drive a '73 240 but the clearences are the same or close . Your question depends on a couple of things . The off set of the wheels and the size of them. I can run 15'' wheels with 205/50 15s and they will clear with about 3/4'' . If I went to 205/60 15s there would be zero clearence and the edge of the tire tread on a left turn, they will hit the lower vallance by the turn signal if it is not modified . Gary