Talking about muscle cars, that would be those born in the 30s/40s because the peak was in the 60s (70s brought emission equipment that pretty much neutered them).
What's really funny as a car guy though is how many people born back then truly believe they had the fastest cars back in those days when truth is if you use comparable models the cars back then could be quick (in a straight line), but very far from as quick as cars from the last three decades! Hell, these days with electric cars it's not even comparable, you can get a Nissan Leaf and 0-60 it will beat most 60s V8 cars. The Leaf does 6.7 seconds 0-60, a Dodge Charger with the legendary 426 Hemi was around 5.5 to 6 seconds (hard to find reliable numbers), the 65 Mustang was over 7.5!
Even ignoring ev's, you can option almost every minivan on the market with 300hp. Any modern hot hatch will drive circles around what would've been a supercar in the 90s, let alone the 60s. There's plenty of things wrong with modern cars, but lack of power isn't one of them.
Another car guy. I had and built one of those old cool cars. They do two things really well: look cool and go in a straight line. No denying the wild styling was amazing then, modern cars are cookie-cutter the same for the sake of aerodynamics, efficiency, and safety. Heck, my boring-ass stock decade-old Honda will do 0-60 in about 7 seconds, and it’s about as exciting as…well, a boring-ass Honda sedan.
Engines back then had massive displacement but the materials science wasn’t there to drop in high HP at a reasonable weight for most cars with those hefty cast iron blocks. Now you can get 500hp without batting an eye on the LS platform, in aluminum, and higher HP is attainable without any extreme work at all. The most powerful V8 stock in the mid 60s was probably the ‘Vette at just over 400hp. ‘50s V8’s probably all put out less than 200hp. Modern stock V8s in some of the cars are just stupid powerful, I think the SRT is over 800. Nuts.
It's also ridiculously hard to compare power because they used to calculate it with the engine bolted to a stand without any accessories while today it's measured "as equipped", so you'll see people talking about 450hp stock on a 426 when it's closer to 350hp at the wheels or something...
Yeah, that’s true. Even today most people do a wheel dyno test vs an engine run in a stand, which is more likely for a specialty engine than an engine with bolt-on mods. I don’t know if 15% is still the general figure for power lost to accessories and transmission, but it used to be a popular number to throw around.