We were pulling camper to Nashville TN. We pulled off I24 toward I65 North. I noticed the engine was raving and it felt like I was missing gears on the transmission. I was roughly 4 miles from my destination when I noticed smoke coming from under the hood on passenger side and flames coming from under hood on passenger side of the hood. I stopped the truck/ camper. Three of us had extinguishers trying to put fire out. The entire engingine compartment burned and fire intruded into driver compartment.