Welcome to the forum. Now that you've been infected with the hitting the road and camping virus be warned there is no hope for a cure.
The engine compartment is tight, the 454 is a great motor but a monster heat producer. I would suggest checking the insulation around the engine compartment. Also check for a heat shield for the starter motor. Heat saturation lock up is a common problem. Maybe some heat wrap for the exhaust pipes. Even the small blocks in Class C's will give you a hot foot when driving so any heat shielding is a great investment. At the first sign of a miss replace the spark plug wires with a set designated for with standing high heat situations.
I had a class C with a small block and remember the heat. I've had many pickups with the 454 and always said it could cook dinner wrapped in tin foil while driving down the road. If driving in the desert I would consider adding some vent ducting for additional air flow to as near the top of the engine as possible.
I still think you have a winning combination. You'll think the gas mileage is terrible but it will be close or better than the small blocks. My 97 454 w/3.73 actually got 2mpg better than my 96 350 w/4.10 in identical trucks and the 454 was a way better towing beast.
