Looks like an ABA with a custom turbo and intake setup on it. If it runs good, I'd leave it alone. That is a pretty good engine, even with the added stress of a turbo on it, so long as it isn't tuned too crazy.
But if you REALLY want to make it a diesel, the 1Z/AHU TDI is the same basic family as the ABA (assuming that is indeed what it is.... easy way to tell is if it has a distributor). So all the mounting, oil pan, etc. should switch over.
The ALH I think would be a better choice, since it is a tougher engine overall, and has a little better aftermarket build support. It will use slightly different mounts as well as oil pan, but the bolt pattern will be the same.
In either case, you'd have to figure out how to make it run.
I worked at a dealer that also sold Suzuki when those were new. I wish I'd have had the foresight to save all the ones left there with blown up engines (and there were LOTS of them). Because we probably sent a half dozen a year to the scrapper, many were in very good shape otherwise. The Suzuki engines are not very robust. Well, the whole truck isn't very robust, LOL. They are cool little machines, though. Especially like the hardtops.
