Question regarding Horsepower GROSS vs NET, 1966 VS 2005

I'm not sure how your calculating those numbers.

Also, a 65-66 Mustang weighs alot less than a 05 does.

Gross is pretty much what the engine will do on its own, without any accessories, transmission, full intake, and maybe exhaust too... pretty much an engine dyno. Compared to that, was the net (like SAE) which was a better idea of what the engine would do off the showroom floor with all of the available accessories (ac/alt/power steer/water pump, etc), intakes, and exhaust components.

Depending on the car, there was some fudging in those numbers, like wanting to make a very powerful more tame to please the insurance people, and making a very weak and cheap car look more powerful. I'm not sure how they fuddled with those numbers, like gutting cats, fake/free spinning/completely removing accessories, hidden restrictor plates, but the two systems are completely different, and so there's really no direct way to convert those numbers. Your best bet is asking some guys that are pretty stock what they dynoed, at least that's a number that's pretty close to apples to apples, except yeah, the 65-66 is a lot lighter than you'd imagine.

Its like DeJaVu