450 ISX?

I had a 435 isx in an Internatioal 9400..We changed the egr valve 3 times in 530,000 miles , twice it was a warranty deal..The EGR cooler started leaking and caused the head to be rebuilt at 400,000 miles. The cooler leak wasn't caught due to our shop mechanic not having the leak checked out properly....I would say you should be happy with that engine ..The newest isx's have many problems , stay away from the 2011 and 2012 models....The 2004 2005 ones got decent fuel mileage and other than EGR valves or sensor troubles , were very reliable..We got around 7 , 7.5 mpg pulling rolltarp trailers around 75,000 lbs..

 

They are a good engine. The EGR is a pain , but there are ways to solve that problem easily . And there are expensive ways.
Do a little searching , you'll find them. Easiest is to unplug the EGR . That's the cheapest , but it must be done correctly, and you'll have to live with a check engine light on forever.
The other way is about $3000.00.