I'm confused - do you mean the starter or whole engine? Because I have considered a 5.9 Magnum if I find any major issues with the LA360 I currently have.
I was responding to another post.....regarding the model of vehicle to use when buying a mini starter.
The 5.9 Magnum is a great engine to retrofit into the classics though. Roller cam, great heads, fewer leaks compared to the LA series engines.