[Junior Guru]

While I haven't owned or driven a Newell with a CAT, I have owned a 2003 3 slide Newell with a Detroit Series 60 and currently own a 4 slide 2013 with a Cummins ISX 650, both with Allison transmissions. The weight of the coaches of course are significantly different, with the 2013 much heavier. I'd have to look up the specs, but I believe they are about 14,000 lbs different. So not an apples to apples comparison for engine performance.

My experience is the difference between the two is more noticeable on acceleration on flatter surface and less noticeable going up a steep incline or when you are at cruising speeds. Both are not winning any speed contests in the Rockies up long steep grades.

The series 60 has a long track record, and if they were available for RVs today I'm sure Newell would still offer it as an option.

I've been happy with both. Hope that helps.