230 5.9L Diesel
Gary,
I have had both 454 big Block and 5.9L Cummins powered rigs, at present I have a 2006 Seneca Duramax powered rig. Of the three different engines I can say the Cummins 5.9L is the best hands down. The 5.9L is a torque monster and well out perform the 454 Gas rig by a mile. I am not sure about your 230 the 305 would be a much better choice, but since this RV is in fact powered by a 230 you don't have much of a choice. but thats cool as there are severeal ways to increase the output safely of this 230 5.9L, it just takes money.
The 454 is a great engine, for what it is, no doubt about it. it is simply not in the class of a diesel like the Cummins. Now if you really and truly want a big dollar disappointment get a Duramax Chevy powered rig. My new coach with this underpowered mess is something else altogether. Go with the 5.9L I don't believe you will be sorry.
Gunny