It's a fine engine alright, but not even really in the same class. The engine would have to put out about 7 mpg at 110 mph average speed, with lots of braking

It's a fine engine alright, but not even really in the same class. The engine would have to put out about 7 mpg at 110 mph average speed, with lots of braking and acceleration and top speeds north of 200 mph. It would need a turbo and significant amount of boost to put out a comparable 850 hp. And not exceed 100kg/hour fuel flow rate. And it's still about 60kg heavier at about 150kg vs. 210kg. All of this is kinda a silly comparison, because an LS engine won't fit in an F1 car and afaik can't be used as a stressed structural member.