A diesel is much more fuel efficient and the trade off is higher priced fuel. As a rule, fuels are sold by their BTU content (more heat value, more horsepower)..also a diesel creates more torque. I am running an 8.3 Cummins C series and according to the Cummins support people, it is very rare to have to put a wrench on the engine in the first 400,000 miles. People are concerned with oil changes being expensive because the diesels hold so much more oil but Cummins recommends changing oil and filter every 15,000 miles. In my book, its an even trade on maintenance costs but overall the diesel is the way to go. Another thing to take into consideration is the transmission behind the engine. You will only find an Allison automatic behind the diesel and they are idiot proof and are the most reliable transmission on the market. A diesel will also have an air compressor mounted on it to operate air brakes. Air brakes are a wonderful thing. I think you need to drive a diesel pusher and see how you like it. 99% of the people will never look back at a gasser.
