GMC Safari AWD looking for the best diesel match

[squints]

I have a 1996 GMC Safari AWD hitop with a 4.3 gas engine. I love the vehicle its quiet roomy and excellent in the snow and light offroad. So far
I've installed a HD alburn posi, bilstein shocks, Goodyear airbags and a number of other upgrades. I plan to hold on to the van for a long time and I intend to use it to pull a trailer as well.
I believe a diesel installed in this vehicle would be a perfect match.
Any help would be appreciated thanks.

[Edahall]

Here's an Astro with a 6.5L diesel.

http://www.youtube.com/watch?v=HnEJJGLhVLs