Most aftermarket electrical fuels pumps will come with everything you need for install. i.e. wire, mounting bracket, some even come with a fuel filter, and additional directions for wiring it into your oil pressure switch for emergency shutoff.
Assuming you are running a stock Hitachi carb or Webber 32/36, you should not require a pump that puts out more than 4psi. 3 to 3.5psi is probably ideal.

You might need:
1. Additional wire
2. Additional lengths of flexible fuel line
3. In-line fuel regulator
4. A new grounding location

You will obviously need to get or fabricate a plate to cover the hole left from the mech fuel pump.

If you are running some type of dual carb setup or fuel injection; I will leave that to someone else.