I would think omori Japan would know about it.

Got everything installed and it works! Added the 3.69 gear and speedo was reading 10% slow, showed 50 when I was really going 55 or 70 / 77 real speed, etc. Found an old thread about speedometer calibration, soldered some jumpers on the speedo itself and it's fully accurate. Even adjusted for my tire size. So using all stock parts, less things to possibly go wrong.

Do you still have that old thread? Thanks

Just search for 240sx speedometer calibration and it'll come up. Main info is the % values for each pin. Look at what are set from factory, then figure out what combo works to get your desired change.

Here is one of the top results.
https://forums.nicoclub.com/s13-and-...p-t618567.html

So for example, pin 7 was only one soldered together. #7 = -12.4%
Difference going from 4.08 to 3.69 is +10%. So -12.4 + 10 = -2.4
Figure out what combo of pins gets you to -2.4 (so 0, 3, 4)
Desolder pin 7, and put a dab of solder on pins 0, 3, & 4.

In my case, I had extra math since I'm running 245/40R17 tires instead of the stock 205/55R16. Those are -0.8 smaller than stock. So to get mine correct: -12.4 - 0.8 + 10 = 3.2

There's 4 part numbers for S14 gauge clusters, so you need to base adjustments on whatever the starting point is on your cluster.