Having retired from the Coast Guard, I’ve seen some big engine start ups. One of my favorites was a 45,000 hp inline 10 cylinder. Each cylinder produced 4500 hp and rather than a single block with 10 cylinders, it was 10 independent cylinders running on a single driveshaft. Pretty impressive, twin turbos that appeared to be approximately 10 feet in diameter. It was a beast but very quiet when running.