Most 33k trucks are using the Cummins pacaar 6.7. Ford is back to using its own 6.7 exclusively in the F750. Most of the others are available in the 9 liter Cummins but they are few and far between. How bad are 33k trucks on power when loaded up in the hills? I am in a hilly area and don’t want to end up with something that is underpowered. I did have an 02 international with a DT530 8.7 and I seem to recall it was okay, not great. Looking at specs, the newer 6.7s can be tuned for the same hp and torque specs that the old 530 had back then, 300/800.
Well the factory engine brake on both Cummins or Ford will be a nice upgrade over the older engines, but I can't help you in the power dept very much, I have driven a f350 to around 30k truck and trailer and you just drive slower