Well you can always read Dragonball Z and One Piece separately. But did you know that you can read them to together as well? In Cross Epoch the mangaka of DBZ Toriyama Akira and Oda Eiichiro got togehter and combined their worlds and characters. It’s a hilarious one shot with all your favorite characters from both mangas. Enjoy this mixed up world in which Hercule is king, Bulma and Nami work together, master Roshi and Sanji cruise around in a cowboy car, and Vegeta is a pirate. And of course don’t forget Goku and Luffy.
And while you’re at it check out the DBZ parody created by Toriyama called neko majin. It’s seven chapters and is really funny. You should read it if you like DBZ or are embarrassed that you watched the entire series and want to make fun of it.