I am not aware of that

They had a bad batch of blocks in 98 they were warranteed. That doesn't take away the fact that overall they were the most reliable engine.

some of the earlier 12.7 liter 60 series had bad piston pin bushings. They'd bust the piston all to hell and put the rod through the block. Remedied years and years ago.

I recently yanked the 12.7 detroit 500hp out of my classic and put in an N-14 525hp. The cummins is twice the engine the detroit was. will run circles around it all day long. But I gave up 0.4mpg doing it. I still like the cummins much much better.

Now back to the OP - both are good engines. The ISX is better, in my opinion. But the Detroit is definately gonna be cheaper to work on.