Update time:
I decided on a mounting strategy for the side transmission mount. Initially I was going to get a 50mm thick piece of aluminum and use the stock bracket to mark out 3 holes and mate it this way. Instead, I found qty 3 x 50mm spacers that have a 22mm OD and a 9.8mm ID. I reamed them to fit a 10mm bolt.
The threads in the transmission are 10mmx1.25, so I ordered up some 80mm bolts to fit the new spacers that will be sandwiched between the stock mount and the transmission case.
50mm is the perfect length spacer. It puts the left side mount in the correct place, exactly. It allows the rear mount to slide in without binding.
The right engine mount is yet to be engineered.
As Kimer pointed out earlier, you have to do something with the thermostat housing because it points straight up, into the bottom of the hood. I decided to acquire a custom, sand cast, one off, bespoke thermostat housing. It's Kubota part number 1G253-73260. This piece turns the water outlet 90 degrees.
Once the mounts were in place it became apparent that my "measure with a micrometer, mark with a crayon, cut with an ax" method of locating the frame rail relief is a process that has lots of opportunity for improvement. I had to lower the relief by about 1".
