DSDP Don wrote:
I have a 40' Newmar Dutch Star that would be a pretty close comparison to the Revolution. It has the 450 ISL. I tow a 6K Silverado and it does a good job, but drops to about 45 on steep grades. Surprisingly, my 2005 Monaco with the 400 ISL did a better job towing my truck and could easily hold 55 mph.
I think the 380 HP at 1050 torque will do the job, but will struggle on the hills with a 10K boat. If it's not a regular thing to tow the boat, as you said, you could probably get away with the Tiffin.
You probably did not have a tag on your Monaco. While your Newmar has a tag and it adds a lot more weight to that engine.