Is 360 hp enough for for 38-40 ft class A

1HP/100lbs is adequate but not a rocket ship. Expect 45MPH on sustained 6% grade.

We have 360hp and have pulled CR-V, and now pull a Nissan Frontier with no issues at all. Good luck!

Our Newmar 40' mountainaire, has a Cummins 350, with a banks kit on it. We have no problems on hills, it will shift down when pulling hard, but it just goes. we have pulled a flat bed trailer loaded to 10,000#. You could tell it was back there but no problems over Stevens Pass on US 2.

I usually worry more about the down hill side. Diesels need added equipment to hold back on long grades.

It's not the HP that gets a MH over the mountains, it's the torque. And these motorhomes have some incredible torque.

For example, the Cummins ISB6.7 has 200-360 hp and 520-800 LB/FT torque (same size engine (6.7L) you find in Dodge Ram pickups). The ISC8.3 has 380 HP and 1050 LB/FT of torque, 8.3L. Bump it up to the next level and the ISL9 has 400-450 HP and 1250 LB/FT of torque. The king of Cummins motorhome engines is the ISX15 with 600 hp and 1950 LB/FT torque. These are the current specs from Cummins website.

It also depends on which model of a brand one gets. For example, the Tiffin Phaeton 40' comes with the ISC engine, while the higher level Tiffin Allegro Bus 40' has the beefier ISL engine. Same length, different engines.

If it were me, I would be checking the torque rating for any motorhome I was looking at. I would hate to think I was buying an ISC engine when it was actually an ISB.

38.5 4 slides towing 7k trailer 330 cummins 950 tk no problems. 45 on long grades could go faster just see no need to burn more fuel to get there 10 min. Sooner.
full time

My 330 CAT 860 ft lbs of torque does very well while towing #5000lbs. Never felt under powered. I can still stay ahead of trucks on hills if I wanted to, but take it easy and let the engine and trans work with out pushing hard to be first. 8-10 MPG too.

We have 350HP in a 2006 39' DP and it does fine. Have been to Alaska and back, through all of the mountains in south west Canada and across the US Rockies several times. Did the 10% grades up at Teton and in the last couple of days did the 11% and 14% grades in southern Utah on Hgwy 12 just south of Dixie Park. We're towing a Jeep Wrangler.

The neighbor make it up the hills a little quicker with his 600HP, but then he paid about four times what we did for his DP.

Bill

Assuming it's turbo charged diesel(and they pretty much all are) mountains shouldn't be much of an issue.

500-600hp is more about ego than need.

As our DP MHs keep getting larger the old rule still seems to apply as a MINIMUM of 100 hp for each 10,000 lbs.
350 hp for 35,000 lbs, 400 hp for 40,000 etc.

My 350 Cummins pulls a 4800# toad and I don't even feel it. I go over the rockies all the time and if that is not a test nothing is!!!