What is your asking price?, and where are you?

Pardon my SARCASM, but....
....Cool car, it's really old, older than me. I've never seen so it must be rare. Let's see old and rare, it has to be worth lots and lots of money.
Like I said, sarcasm.

Google Nissan P0500, you will find several pages on vehicle speed sensors, or if you have a factory service manual there is information on how to test yours. Most are pulse generators, in Nissan's case, 4 pulses per revolution. While I am not certain, it's been a while since I played with one, I think that they use a hall effect to generate the signal, a simple way to find out is to connect an analog meter to the 2 wires and rotate it, if the needle "bounces" you should be good to go.

OK, I'm not trying to start a pi$$ing contest here, I've spent 40+ years working on cars for a living and I have seen a lot, not everything, no-one could, that said this is based on my experience. Knock, ping, rattle under acceleration, funny noise, pre-ignition, detonation all cause engine damage. Over time you should see erosion of pistons or combustion chamber, broken spark plug porcelain, or a combination of the above. Detonation does not just cause a broken ring without other damage being obvious. Like I stated before maybe you need to take a good look at everything and not be quick to blame it on one thing, and it might be a good idea to get someone else to look at it also, most times two or more pairs of eyes are better than one. IF you still come to the same conclusion here are a few things to consider, richen up the carbs to see if it goes away, a "wet" mixture is less prone to pre-ignition because it's cooler. Try a step or two cooler spark plug, incorrect spark plug heat range can and usually will cause problems if your not sure what to use ask around to see what others are using, and finally look for vacuum leaks, they will cause a lean condition in 1 or 2 cylinders. Again, GOOD LUCK.

Is there any obvious damage to to piston it's self? Detonation or preignition will usually cause damage to the piston it's self or the cylinder head before breaking rings.
Are the ring lands deep enough to allow the rings to properly compress? As in are the rings the ones called for by the piston manufacturer, there has been a lot of talk about using pistons for other engines to increase displacement, not a bad idea when you can't get what was once available, but different brands use different engineering specs. I guess what I'm trying to say is that there could be many reasons for a broken ring and detonation isn't the most common, might be time to start to consider looking any and all possibilities.

Here is an alternative 84-89 300ZX 2+2 louvers are just wide enough to cover the rear glass, however you will need to shorten them by 1 louver so that you can open the trunk (boot) lid. My car is buried in the garage right now or I would include a pic.

Take a look at a few other things, it's possible that it broke during installation as in your ring compressor didn't fully compress the rings and the ring caught on the lip and got broken while being installed. Another thing to look at is if there is a ring ridge in the cylinder walls, Nissan blocks are hard and don't usually need a rebore from wear, but I have seen it happen on occasion. And as a last thought if the rings are too large for the bore as in insufficient gap when installed will cause rings to break, check the ring gap before installing them on the piston. Good luck.

Probably not without some work, the instruments are on different sides. The wiring will probably need to be reoriented to be able to hook up the gauges and switches. The wiring goes through the firewall at the right front corner of the engine compartment on LHD models and seems to do the same on RHD models, that would give you about 2 feet (60 cm.) difference in where things hook up. Also the plastic wire holders at the harness connectors are probably different too.

This one, about 14 years. Which begs the question, when did you first get a 1200?
I bought my first one September 1974.

McCarty Auto Parts USA-GA(Hazlehurst)912-375-2675 /800-329-7258
Nuwer Auto Parts USA-NY(Holland)1-716-537-2800
Frank's Auto & Truck Parts USA-TX(Brownsville)1-800-882-4349
Parts World USA-OK(Roosevelt) 580-639-2308 / 580-639-2242
The only ones showing in the US at wrecking yards.
GOOD LUCK!