A very unique 782 repower

[Mudrig150]

I think that this repower job is unique enough that it deserves its own thread for all the issues I encounter with it, and progress updates.
My IH built 782 originally had a series 1 KT17, was swapped to a series 2, and then I got it with no motor after the previous owner ripped the motor and wiring out to repower a log splitter. Not like I wanted the engine anyway.
Was originally going to repower with an M18 from an 1811 I bought for parts but I discovered that it actually had a catastrophic internal disassembly stemming from the governor gear exploding, which punched a barely noticeable hole in the block and took a chunk out of the cylinder jugs. Other than that it looked fine, but I filed it away in storage for another day anyway. I was stumped on what to do until I had an idea come back to me from way back when we first got our X485: water cooled kawasaki swap.
Snagged an FD620D from a 3205 from Patton Acres, it's a relatively low hour engine but it was neglected and thus has some serious carb problems.
My entire goal is to do this swap without majorly modifying the tractor in any visible way (ie. hacking a giant hole in the side panel or whatever). The engine swap should be as subtle as possible, almost like a sleeper tractor.
So far I've had a handful of challenges to overcome, and my full list to finish the swap is as follows:
1: Engine mounting. Engine was actually super easy to get mounted, just needed to space the engine up a bit and drill 2 holes in the mounting plate. The engine length and crank height are so close that spacing the engine up was all I needed, it barely clears the hydraulic lines for the front hydraulic lines and the rockshaft. The engine actually fits entirely within the original body panels with no cutting and I just need to make some air baffles to direct air through the radiator.
2: Driveshaft. Been searching for a shop to shorten the driveshaft for me, the factory driveshaft doesn't fit because the front flex couplers smash into the bottom tank of the radiator, so I had to use the 2000 series driveshaft instead. I could've gone with a CV driveshaft but it would need shortened anyway and I figured the mechanically simplest option would be my best.
3: Fuel system. Was super simple, actually. I haven't bought a fuel pump yet, but for fuel storage I just bought a fuel tank from an early 90s cub lawn tractor that goes beneath the fenders along with the fender mount brackets. It's basically a diesel tank but it doesn't have the hole for the dipstick and no cutout on the bottom to run a rear PTO, but the tractor doesn't have a dipstick for the transmission and I had no plans of running a PTO anyway.
4: Electrical. Actually surprisingly simple. I have the CDI box but no voltage regulator, which originally made me nervous, but it turns out that the harness connector on the engine is only comprised of 6 wires: 2 for the regulator, one for the oil pressure light, one for the temp light, one for the starter solenoid, and one for the 12 volts to the CDI box to fire the coils. Honestly not too bad, all considering. I will figure out where the battery will go once I get the tractor more together.
5: Muffler. This is my biggest issue. I haven't found a single muffler that fits, that I can actually still get, and has the outlet out the grille. I will figure that out eventually, but I'm stumped for now...
6: PTO. Easiest part of the entire swap somehow. If I had gotten the engine from a green machine the stubby 1 7/6" diameter crank and lack of mounting holes on the front of the engine would've screwed me over but the 3205 actually has a standard 1" diameter shaft that the M18 PTO off the 1811 fits straight on, and the bolt holes in the front cover match up too. The mounting holes are the same distance apart front to back and the engine is the same distance forward as the KT17 so the PTO is lined up perfectly with the mule drive pulleys on the FD620D. I just need to get spacers for the bolts since the front cover has a lip that the PTO sits on that leaves a gap between the backing plate and the bolt holes.

I know the easy part is behind me and I'm not looking forward to figuring out all the logistics of this swap but that 20 hp is gonna be so nice when it's running and driving.