Engine swap in an 85 Isuzu Hombre ?

I just found an 85 Isuzu Hombre at the charity where I bought my Crown Vic, the description says 198,000 miles and unable to drive faster than 40 MPH.

With that many miles on it I figure it either needs a new catalytic converter (I say that because my car is still going strong with nearly 175-180K miles) or a new(er) engine.  If you were doing an engine swap on this truck and ease of transplant (not looking to do massive amounts of fabrication), cost of engine, and availability of parts were paramount, what would you swap in there ?

I am guessing a 4.3 Chevy would be easiest, or maybe a 3.8 Buick?  I would even consider a newer 4 cylinder engine if the power was there and price was not astronomical. 

Anybody have experience with this swap?

85 would have the 1.8 inline 4. the 2.4 out of later Troopers/p'ups, etc is a straight bolt in. Not much power, but tough and simple.

I rebuilt a 1.8 in my 85 p'up, skimming the head, with some light porting. It ran pretty strong.

So, this is the Isuzu that is really an Isuzu, not the Isuzu that is really a Chevy S10? 

In reply to John Welsh :

S-10 based Isuzus didn't come along until 1996.

One of the 4 cyl Isuzu diesels. Not sure which version was in the p'up but it was tough. They made a lot of different versions. Our ditch rider had one for his work truck & it had a bajillion miles on it, the p'up was falling apart around it. 

I'd go look through Duster13's Miata challenge car build and copy his engine and transmission build.  I doubt there's any engine you actually want that would bolt to whatever transmission is in the truck.  I second the idea that it's probably a diesel and always slow since new. 

The 2.4 later Isuzu engine gets my vote. 

16v92?