Does anyone know a website that can show me how to install a MSD ignition box or MSD spark plug wires in my Z? Or, does anyone have any tips or words of advice?

 

MSD box should come with instructions, unless you got it used. Try MSDs website if thats the case.
Spark plug wires are not hard to understand how to put on, its putting them on that is the hard part.
I hope you have small hands and skinny arms, you will have a hard time with number 8 and number 2 is easier to get if you remove the alternator. Some of them you change from the top and some from the bottom.
If this is your first time doing plugs and wires on an LT1 Fbody see if you can get a friend who has done it to help you.
It can get frustrating but take your time and if you get stuck post on here and we will try to help.