I have seen one person mention the Chevrolet LSx engines.
What Chevy has managed to do with the LSx while STILL using pushrods and 2 valves per cylinder is incredible to me.
The 7.0 LS7 from the Corvette C6Z06 revved to 7000rpm. That would've been UNHEARD of in the old pushrod days.
The 6.2l supercharged LS9 in the Corvette ZR1 makes 638hp on low pressure and low revs. I think it redlines near the 6.5k mark.
Now these LS engines also have dry sump oiling systems, making them more amazing for the track.
And in the new C7, Chevy has managed to put in variable valve timing AND direct injection into a pushrod V8. 460 horsepower from the base model... WOW.
And I'm surprised no one mentioned the DOHC 4.6L from the 2003-2004 Mustang SVT Cobra. That engine has such a big power potential it's ridiculous. It was rated at 390hp from the factory when they knew for a fact it made more. The sound of a high-compression Kenne Belle supercharger will make your hair stand up.
I'm a fan of American V8s if you can't tell...