Disclaimer: I don’t know what exactly has been done to this car as far as modifications though I don’t think it’s much. And I’m not great with wiring 

 

At first I was thinking I had a zx distributor but if it was a zx distributor wouldn’t it have a little box on the radiator side of the distributor? But the igniter(?) Block inside the distributor doesn’t say pertronix on it so I don’t think that’s what it is
 

And then my tach currently doesn’t work but I have voltage at the red/black wire on the tach, that varies with rpm so I think that means I’m getting tach signal and it should be working. So does that mean the tachometer itself is just broken?

Lots of missing information here.  Kind of seems like you meant to post a picture.

A 260Z probably uses the blue wire from the coil negative terminal to provide the tach signal.

Edited June 20, 20204 yr by Zed Head
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Right you are @Zed Head! 
 

So the pictures show the block inside the distributor and that there is no box on the outside of the distributor. (Disregard that water block off. Haven’t fixed that yet) the blue wire is on the coil negative, the inline resister for the tach is present and plugged in (previously wasn’t plugged in) and the tach has voltage at the positive and negative posts and the red and black wire.
So I think the tach should be working unless the gauge itself is broken 

The old tachs do definitely go bad.  I put a 78 tach in my 76 after the tach needle started getting stuck when it got hot out.

That looks like the magnetic pickup for a stock 260Z ignition system.  Looks like you have a stock ignition system.  I assume that the engine runs, but the tach needle doesn't move.  Does it move at all, ever, when you turn the key on?

@Zed Head I thought this car should’ve had points originally? It runs quite well, it drives, idles great and starts right up. Just the other day I moved the wires off the ballast resister block (is that what it’s called?) because I thought that those were for points and I don’t have those. 
 

As for the gauge, the gauge lights work, the left arrow indicator blinks, right arrow doesn’t blink and the tach doesn’t move 

The first electronic ignitions were just points replacements, not "high energy" so they still used the ballast.  Your 74 is the first year of electronic in the Z's.  Look under the dash by the fuse box and you'll see the space age module.  

You might burn up the coil or the module if you run without the ballast.  You're letting more current through parts that weren't designed for it.

The ballast went away in 1978 when they went to a high energy (current limiting) system.

73 was the last year for points. The 74 260 was the first year for electronic ignition.

 

Oh, and Zed Head types faster than I do.    

Edited June 20, 20204 yr by Captain Obvious

Alright then. I’ll put those wires back and get another tachometer. Thanks!