Hi from Australia,
I probably have the ugliest b series on this forum.

Bought it from the original owner,
They handed me an old heavy bag before I left,
which contained the original purchase documents, entire service history and receipts from 1986 to 2018 when they stopped using it.

I found out later whilst going through all the receiptsand paperwork that the motor and box were rebuilt in 2016. WIN.

Paid $700 cash.
And it had registration so I drove it home and have driven it pretty much every week since.

One day it died in a carpark, then a week later it flooded after I filled it up with fuel,
So I decided it was time for the original carb to go.

Did the usual engine bay clean-up,
deleted all the vacuum and egr stuff,
wire cleanup and put a genuine weber 32/36 on it,
which needs a bit of fine tuning (thats how i found my way here thanks to the mazdamitch youtube channel).
I whipped up a 2 1/4 exhaust for it thats dumped before the diff,
Punched the egr related junk out of the exhaust manifold and capped the openings for now,
I will fab up some headers when i get some time.
Just did the water pump, timing belt, oil pump, etc a couple of months ago for peace of mind.

Iv been in a heated battle with the dash lights on and off since iv owned it,
They would just flicker and never stayed on more than a second.
Tried to bypass the switch every way I could think of with no success (I work in an auto electrical and mechanical workshop)
I then took the switch apart and removed the factory mini pot from the circuit (cut the traces, ao the thumb wheelcould stay in place for aesthetics) and wired in an generic mini pot, which got the dash lights working!
For a few months,
Now they just switch on and off every now and then when they feel like it, sometimes they stay on for the whole drive with no issues.

Iv tried to replicate it by moving the wiring harness and components etc, nothing changes.
Maybe thermal related,
Maybe coductivity in the board, not sure... yet...

One day I'll pull it apart again and trace the board to figure out exactly what that circuit is doing,
And see if i can replicate it on a breadboard or something.

Back when I messed with it I did read 2 or 3 people online say just bypass it, but iv seen zero proof of anyone successfully bypassing one or any follow ups.