best year ISX to buy?

IMO, Pre EGR ISX, no EGR, no VGT, no SCR/DEF/DPF.... 2002 year

 

The '07 was the year they made the switch to DPF, but those built b4 January of '07 (they start making the next model year in the middle of the summer) did not have the DPF. I have an '07 without. Been through a few EGR's in 500K, and have doubts about how much longer this original turbo will last.

 

what a reason to purchase newer engine with expencive parts? '02 ISX is available rebuilt, no VGT, EGR!

 

I use old CM570 ECMs to remove EGR and VGT (non VGT turbo is much chepper and I can use BW, Schwizer ore Garret, not Holset only).

CM870 require old fueling solenoids, but they are twice cheapper new

 

If you thumb through truckpaper you'll see that most, if not all, 99-03 trucks with an ISX have had the engine completely replaced...much like the early C-12's. But as you said, finding something without a gozillion miles is a challenge.

 

really lets compare pre EGR ISX w CM570 and Newer with CM870

Newer got new metering solenoidds (not compatible with other), new cyl. head with other timing, EGR and VGT.

 

03 - 05 ISX also have a tendency to develop a leak in the head gasket on the drivers side rear of the head. Begins small and turns messy leaking oil all over the place. If you find one you like be sure to check this. Otherwise it's a decent engine. I have an 05 and it leaks there but still turns 97% of the factory HP rating and gets 7.9 MPG loaded.