I have a few ignition questions please. Here are the first 2. 

1.  the black wire (with yellow wire). Any idea what it is or where it goes. It was broke off when i bought the car.

2. the other green circle  beside the  the red wire has a fork that goes somewhere. Should it just go under one of the screws?

thanks much

Might be shown un one of the 71 240Z diagrams.

Use your meter on that forked black wire and see if it's a ground wire.  

https://www.classiczcars.com/files/category/1-wiring-diagrams/

Here's a photo of my 240Z distributor with a Pertronix Ignitor 2.

Background: In 1997, I replaced the points with a Crane optical ignition. It failed in 2010. I replaced the distributor with a ZX distributor in 2012. In 2020 I stole the ZX distributor to replace a bad distributor on my 260Z. When I decided to put the 240Z back on the road, I found the 240Z distributor and decided to install the Pertronix.

As part of installing the Crane ignition, I removed the insulated with with the fork that you have circled in green. The female spade terminal you see at the 10:30 position of the distributor is part of the ground wire. It is not connected to anything now. Previously, I believe it was connected to the ZX distributor. My car runs fine without either of the two wires you are asking about.

thanks all. that was a big help. 2 more questions on this ignition if i may.

I think i have the ignitor II setup as well. I have the red wire hooked up on the coil right, but the black wire i circled in image 2797...does it ground to the chassis? I am thinking thats where it was originally

Last in image 2798. I know i have one end of wire hooked up properly on the ballast resistor mount (at least thats the way it was when i bought the car originally). I can find where i put the other end though?

Do some research and tell us what you think. https://www.google.com/search?q=pertronix+ignitor+2+wiring+diagram&sxsrf=AOaemvLgcSyHv8UYGS5GmC6Xxz33YmNGrQ%3A1633911242656&ei=yoFjYcq7J4KHggeR8bvQDg&oq=pertronix+ignitor+2+wiring+diagram&gs_lcp=Cgdnd3Mtd2l6EAEYADIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQRxCwAzIHCAAQsAMQQ0oECEEYAFAAWABg7dEBaAJwAngAgAEAiAEAkgEAmAEAyAEJwAEB&sclient=gws-wiz

I did some. A couple videos said not to use a ballast resistor with this setup. However, the car came with with the pertronix and and resistor was installed. I did take a few photos of this before disassembling everything for paint. The car did run....not that great admittedly.

So that confuses me a little. Do i use the resistor or not and if not then what to do with those extra wires too..

The setup in this google search seems fairly simple but again there will be a lot of leftover wiring....maybe that is normal though. I may need to outsource this part of the re-build 

No, there will not be a lot of leftover wiring. I'm not sure what you mean by extra wires.

Pertronix has the basic instructions on their website for installing the ignitor.

It shows where each of the wires from the ignitor should go. Notice the specifications. A resistor in series, like the ballast resistor, will drop the voltage. The voltage should still be within specs for the ignitor.

The intent of the ballast resistor is for protecting the points. The condensor at the coil also contributes to the protection. However, with the ignitor, you no longer have points. So should you get rid of the resistor? That's up to you. However, you don't just leave the wires dangling in the engine bay. The wires at the ballast resistor have to be connected together if you bypass the resistor, otherwise, the car won't run.