Here's the Buda 6B230 block that came with the tractor, likely from a Cockshutt 40, I was OK with using it but then I got the bug to find a real one, it's mostly cosmetic so it must be Orange Fever!

My new authentic 6BD230 block - more spare parts I guess.

It's fun having two engines but subtle differences do raise questions. One oil dipstick has a handle all four fingers fit through and the other has just a small round loop for one finger.

Odd the oil levels differ even though oil pans are exactly the same.

The new block was taken to Precision Bilt in Minneapolis.
They stopped long enough for me to get a few pictures.

Close-up of welds before and after the first pass,
before the counterbore is adjusted.

With counterbore machined down, shim added, and sleeve height adjusted

Alignboring is necessary after welding and machine work.

The sleeve height should be about .002 above the deck