I purchased a set of UK dials last year.

Today was going to fit them however the back electric sockets are different to mine!

My Z is a TT jap import. I thought it might be a simple change.

Apparently NOT!

Advice please 

Art

Lots of posts related to this - I did exactly the same as you when I imported my Zed and hit exactly the same problem. I’m assuming you want to get your Speedo into mph? Choices are:

1) Fit a km/mph converter box behind the cluster;

2) Get a replacement speedo dial and replace the existing dial face;

3) Practice your 16x table and do lots of mental arithmetic;

4) Take a brave pill and take a soldering iron to the cluster/connectors (instructions are on the forum somewhere)

Other options may be available, these are just the ones I considered. I went with option 1 for several years, but got fed up with it messing up the weighting on the power steering and HICAS, so I got a replacement dial face (https://lockwoodinternational.co.uk/product/nissan-300zx-mph-dial-part-no-c1528/) which works a treat although it’s pricey for what it is. There is another gotcha too as there is more than one shape to the mounting bracket for the dials depending on the type of cluster you have!

Good luck whichever option you choose.

What age is your car? 

If it's a series 1 / series 2 in compatability, you can remove the speedo unit and mile counter from the uk clocks and fit it inside the case of your jap clocks

If the car or the clocks are series 3 to 6 and the other is series 1 or 2 then you can't do that

You need to tell us the year of your car and to show a picture of the cluster you have bought, front and rear, a seller might have said they were UK but there's no guarantee that this is the case.