Stone is correct in that the 330 has an output of 108bhp. But remember this is probably for a new engine. Every engine will vary considerably. I've driven artics that are rated at, say, 460bhp, but every truck will pull differently. An engine will work better if it's been pulling maximum weight since new. I've driven trucks that were used on very light work. Once you need to use it for heavy work they die up hill, where as the same make and engine size of a truck that's been used on maximum weight all it's life will go far better. Don't know why this is though?
The MJ's are very under powered in my opinion. A Reo is (I think) 8 litres and 140bhp for equivalent total weight. The bigger Ural 4320 has a monster 10.8ltr V8 diesel producing 240bhp, plenty of engine for the size of the truck.