What am I missing here? $4950 buy it now? I know the engine is toast but ???

There is much discussion about this motor home. It originally had a GM 6.5 diesel in it and the original owner had the duramax installed. Unfortunately, it was the early Duramax and someone did something that caused it to blow. The early Duramax engines had an injector problem but I wouldn't think that would cause the engine to blow. To install anything, i.e., a Cummins or a later Duramax, would involve extensive rewiring/computer work, etc. That being said, it's very nice inside but does have something in excess of 50000 miles on it. For someone who is very good at the mechanics, it would be an interesting project. The Spartan chassis has a 172" wheelbase. Do a 'search' and enter 'duramax' and you will get all 4 pages of the post.
Jim

If this had (very likely) the 4L80E tranny, in stock form, it wouldn't have been able to handle the Duramax torque. And as Jim mentioned, the early Duramax weren't celebrated for durability or reliability.

Nevertheless, this hulk would be a good start for a resurrection.