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[TerryS]

If you're sincerely planning on getting into a Defender 110, you need to do lots of homework.

Adaptation of various engines in the land of Oz are genergally well thought out, based on the engines available to them, and not necessarily what is done in the UK or the US. The Isuzu engines used in their larger trucks are very good engines, and have been transplanted into lots of non Isuzu trucks.

BUT...............

You are going to find fairly quickly, in investigating the loads of Defenders for sale in other countries, is that they are, for the most part, unavailable to buyers in the US. The general rule of thumb, cast in fairly rigid terms by the NHTSA (National Highway Safety Administration) is that in order to import a vehicle less than 25 years old, it must (A) be imported by a Registered Importer, (B) be made to meet many standards, the conversion of which requires baskets of cash, (C) have a bond, equal to 100% of the vehicles value posted, guarenteeing it will be made to meet those standards, and pass scruteneering by EPA and DOT examiners (failing that, it must be immediately exported, or destroyed)

The value of the original pool of 535 legally imported trucks, in 1992-3, is now somewhat less, but highly inflated by virtue of their "exclusivity".
There are many trucks around, not from that original 'batch', which fall into several catagories; imported legally and made to conform, assembled here and legally registered as either home built, or reconstructed from NAS D90s (see ECR) and those which are not legal, imported with false documentation, such as titles and ID plates from trucks over 25 years old (no 110, or Defender 110 is over twenty five years old) such as 109 series trucks.
Many of the original NAS 110s are getting pretty tired now, and in need of rebuild, so getting one of them is not as expensive as some of the rediculously priced ones from places like ECR of Copley Motorcars. They aren't as difficult to rebuild (and rebuild well) as some would have you believe, and in the long run, are economically competitive with going to import route.

I'm not sure if I answered your questions, beyond, yes, Isuzu engines are good 'uns.