Carb, or FI? How much HP are you planning on. If you plan on running a carb with a mild V8 no changes are needed. If you will be using the 289 in your signature, you should be fine with the stock lines.
Carb needs no return but FI does. FI also has special tank considerations. You need baffles or a purg tank to ensure you don't have fuel starvation.
I never understood why the Z needed such a complex venting system. Lots of guys here simplify it.
Any mods you do to your tank need to be done with care not to cause heat or sparks (loud noises and bright lights followed by nice people in medical smocks ), i.e. don't drill, grind, or saw.