Cummins 600 sig or X15 565
Looking at buying a 389 with a 600 sig or a w9 with a X15 565. I’m leaning more on the 389 as it’s exactly what I want in a truck inside and out but have never heard of or know anything about the 600 sig. Any insight, pros/cons on this engine would be greatly appreciated. Buddy rebuilt it with ATL rebuild kit about 35k miles ago. The IX15 has about 5k miles on it.