Since I begin towing my Jeep and not driving it to the trails, I have had a gasser. One reason,...$$$ I could not justify the cost of a diesel for no more driving I did with it other than towing. I started out with a Jeep truck with a 304, T-18, and Dana 44's with 3:54 gears. It got me to every place I wanted to go. Just not as fast. I settled for 25-35 on the major hills. I took me longer, but not that much longer. I have worked that little 304 good for 6 years. I changed oil in it every other month. Usually only had 1000 to 1500 at the most on the clock, and usually really not that much. But, I figured it was cheap insurance. I don't use high dollar oil either. I use the 10w-40 Super tech from wally world. In all my cars. I use either Fram or Motorcraft filters.
It's been a long time, but when I worked at the machine shop I read some literature on oil and viscosity break down. Biggest contributor was heat and contamination. So, I figured pumping as much fuel through it as I did, 8-9 MPG and run as high of RPM's as I did on the hard pulls, it was needed as often as I did it. I had the intake off once and it was as clean as if it had just been built.
My son owns the truck now, so he will be towing with it just as I did. I now own a Ford van with a 460 in it. Gets me there and back a lot faster, with some creature comforts while camping.
Would I like to own a Cummings or power stroke, yes, I would, can I justify the cost? no I can't.