Miller machine differences

[Broccoli1]

Looks like the X designates that it is the International model.

[cruizer]

Seems to me that if I replaced the process switch out of a PP350, and added the arc control pot, I'd have a PP350 with a Pro400 name plate for less $$

[cruizer]

Ok, something I don't know.... What is thee difference between a Big Blue Pro 400 and a Big Blue Pipe Pro 350. . Other than the PP350 doesn't show the Kubota as an option, and the Cat Turbo isn't offered with the Pro. I see no real difference on the schematics, and the part numbers being the same. The price difference between the 2 is quite a bit. So the difference being the engine choice? And what is the difference between a Pro 400 and 400X