I would contact DDC and see if they had any horizontal mount applications for the Series 60 engine. If they do, then you would be able to do the swap, so long as you purchased the required components to allow for the engine to receive proper cooling and lubrication. For the cost, I'd stay with the old screaming meanie.
1994 Safari Sarengeti Edition 37' diesel pusher
1997 Ford F150
1998 Jeep Cherokee SE 4x4 (toad)
2006 Chevy Aveo LS