I too have swapped out the original 240Z dizzy (European units are supposed to have a better curve but hey) for a second hand 280zx unit and module, the main reason was eliminate the possibility of inconsistent spark at high rpm

Replaced old ballast coil for a Bosh blue sports 12 volt unit, bypassed the ballast, whole thing took 30 minutes tops

As was posted previously, very smooth, well past 7K and the tacho still works perfectly

Previous to the swap I dyno'd the car and noticed ignition scatter around 3.5 K + and a small misfire at around 5.5-6K probably due to points, general wear and a 30 year old coil

Re dyno'd the car - hey presto no scatter no misfire

Total cost approx £100 (about $170 for you ex colonials :classic: )

Regarding plug wires I would replace mine every 3 or 4 years irrespective of how good they look - I used to work in a lab working on UV camera analysis of HT arcs and coronal discharge-- Faraday cage heaven -- its amazing what the human eye cannot see.

did the ZX swap on my 240, The tach will work but you have to hook the wiring up correctly, don't remember how off hand but found a diagram on the web.

It worked great until the 20 year old module died a couple of days ago, $124 for a new module, $106 for a rebuilt dizzy w/module, looks like I'll be getting a new dizzy!

I did the 280zx dizzy swap, it was the difference between night and day! my '71 revs all the way up to 6K rpm, whereas before it was a struggle to get over 4500.

I do have a question though, Is there a way to test the modules? I've picked up a few of these from boneyards and would like to have a known good one for back-up.

Don't know how to check the module, I tried ohming out the bad one and got no reading, when the new dizzy came I didn't mess around with it and just stuck it in.

I do know that you can check the pickup coil in the dizzy, with the dizzy out connect an AC voltmeter to the red and green wires and give the shaft a spin, you should see the meter read some voltage that will vary with the speed the shaft is spinning. I did check that.

If you have several spare modules I would try ohming them out, looking for a forward/reverse differantal between the two input connectors and the two outputs. See if the modules all read about the same or maybe one of them reads really far out from the others and figure it's either the bad one or a good one