Well I've spent the last 2 days running the 1912 trying to get it dialed in and I've found three problems:
1. It idles like crap. It really struggles. It doesn't even out with choke and runs like it's flooding but there isn't an adjustment for the idle mixture so that's a problem I straight up can't fix.
2. It blows oil smoke on and off. It doesn't do it constantly, but it definitely does do it.
3. It has a horrendous bottom end knock. It sounds like a rod is about to punch through the side of the block at any second, and it's definitely not valve related. I think it's kaput, which is a shame because I haven't even driven either of the tractors that the engine has been mounted in. I'm gonna see if I can gain access to the inside of the engine to see exactly what's going on but I don't think it's going to be good.

Got the valves adjusted, fuel system hooked up, and ran it for a bit to get it warmed up. Runs a lot nicer with a fuel pump and a tank instead of gravity feed through the fuel line.
Will go to the shop and get the driveshaft for it tomorrow.
https://i.imgur.com/xTYte8w.jpeg

1912 had its first drive today! Made a few minor errors while putting it together including forgetting the suction tube and the expansion plug for the front of the transmission, thought the transmission was blown up because I forgot to tighten the hydro filter, but it runs and drives!
Still need a steering box to fix the backwards steering, the pressure line to the hydraulic valve, axle seals, a harness, and a choke cable, and a bunch more small parts. Electrical is going to be a whole thing but honestly there's been worse parts to this project so far.
https://i.imgur.com/qWxpEXw.jpeg

Aside from all the great work you are performing , I think you need a bigger shed
Oz

I think we need less green ones in the shed taking up space. Had to pull the half dying 332 out to get the 1912 pulled out through the door!

Just working on cleaning her up a bit and getting a harness made. Seat's looking good on there!
It's so funny parking it next to the 655 because the 655 feels like a huge tractor but the 1912 is only a few inches shorter in terms of height and width, not counting attachments. Wheelbase is exactly the same, hilariously.

https://i.imgur.com/JEfFK2c.jpeg
https://i.imgur.com/YfdZYcJ.jpeg

Batch of parts for the diesel. They look awful but should clean up well. Good grille casting with a good IH emblem and headlights, seat and brackets, fender pan with taillights, and a dash for parts.
https://i.imgur.com/Qu2Lm9z.jpeg

Diesel is slowly going back together. Eventually I'll have to pull it to the front and pull the engine to replace the starter and some annoying to reach gaskets. Going to be doing some fab work, taking a firewall from a parts tractor and modifying it to go in front of the battery to do three things: keep the battery from walking off the tray due to the front being cut off, give some support to the hood to prevent it from breaking the top of the dash again, and also to keep the battery from shorting against the hood if the hood breaks the dash again.
Shame the hood (not pictured) is so bad looking, they seem to have sanded all the red off and then shoddily painted it white. I don't have the kind of money that people want for an original diesel hood, nor do I really think that it's a huge priority thing to buy given the leaking injectors and the completely gutted and rotten muffler...
https://i.imgur.com/31wh8Cn.jpeg

Had all three 82 series out today to swap them around a bit.
https://i.imgur.com/7HINr5v.png
Diesel is running and starting great following a minor overhaul (firewall to support hood, glow plug relay, new starter, repaired wiring to the starter solenoid)
Found a very "professional" implementation of a brake switch bypass that was making the starting circuit totally non-functional (starter would click but wouldn't actually spin).
https://i.imgur.com/oXXv4Ni.jpeg
I banished the 1210 to the back given its current non-running state with the completely worn out K301 so the diesel, that actually starts off the battery now, can be at the front of the shed. Also got the diesel cleaned up a bit. Still a few more things to fix on it, but it's a massive improvement to what it was when I got it.
https://i.imgur.com/rDvcwmV.jpeg

Had the diesel out moving a bit of scrap. Ground's super wet so it spent half the time spinning the tires but I made it with ample use of the turning brakes. This tractor runs better and better every time I run it, the blowby is completely gone and so is the surge at idle.
https://i.imgur.com/Ic6de2r.jpeg