If it was me i'd buy a whole car when one came up and swap drivelines. All the add-ons aren't cheap, that is what makes that one in Brisbane quite good value as even if the engine needed a rebuild (would only be rings and bearings if anything as it has done stuff all kM) the accessories aren't cheap.

I bought a whole 350, TH350 out of a HQ Dr Terry had sitting in his workshop for a while for about the same money and it only had manifolds on it. The one in QLD has extractors, crossmember, tailshaft and I think speedo cable too. I'm sure he said he had the whole exhaust too but it was wagon.

The good thing about a TH400 is afaik an M22 Muncie will bolt in its place (same tailshaft, yoke etc, just a new speedo cable).