The 375hp number for the Lincoln engine is almost certainly gross, and not net hp. They'd run the test on the engines without the accessories like AC, power ste

The 375hp number for the Lincoln engine is almost certainly gross, and not net hp. They'd run the test on the engines without the accessories like AC, power steering, power brakes hooked up. That stopped in the early '70s with the switch to net numbers. I would not be surprised if by '74, the Lincoln 460 was making ~190hp as we would measure it now. Of course, comparing it to a modern Mercedes 4-cyl is a silly apples-to-shortbread comparison. Nobody was optimizing for specific output in the 1960s when the Lima V8s were designed. Whatever engine you put in a Lincoln back then had to first be able to move a 5500lb+(!!) sedan off the line, working through a not-terribly-responsive C3 automatic. Bottom-end torque was the key, and in europe, cars of that mass were often diesel for that reason. In the US gas was $.22 for 4L or so, so a giant V8 with 8mpg was an acceptable solution. The Ford big-blocks were also popular motorhome engines for that reason; many are still running today. ...which is another thing. Those engines were huge in both displacement and packaging by modern standards, massively heavy (cast-iron or forged-steel...everything), and of fairly conservative valvetrain and fuel-system design. While this meant there was a limit as to how efficient you can make one, it also means that they can be maintained almost indefinitely with only modest expenditure of time and money, a statement that I don't think has ever been made about AMG engines of any recent vintage....