Interesting information, thanks guys.

So, there seems to be at least a remote possibiltiy that this sort of swap would work. I guess what it will take is a side-by-side comparison of the units to see whether the front case of the 2WD is the same as it is on the 4WD. If so, I guess it would be possible (although the length issue is still present, but that's much easier to check - just need a measurement of the thing).

1988 Isuzu Trooper LS
2.8l Isuzu 4JB1-TC intercooled turbo diesel
www.dieseltrooper.blogspot.com