Engines make horsepower via torque. This is from the article linked above -
HP = (torque x rpm)/5,252
Horsepower is a function of Torque !! There have been some great past threads on how much Torque or HP one "should" have based on the weight of the coach !!
I have a Jeep with a straight 6, and I swear that my RV pulling that Jeep is faster than the Jeep !! lol
My Torque is between 1250 & 1350 foot pounds and the HP is around 425. The coach weighs 33,250 and the toad (jeep) 4,500 lbs. for a total of around 37,750 lbs.
You may have to do some math, but look at the weight of the coach you're interested in and the torque or horsepower. And ALWAYS take a test drive !!!!