I look at it this way, the windsor small block was designed in the fifties and lasted until the early '90s (Ford Aus stockpiled them to last until 2002). It's an old design that originally only produced somewhere I think between 100 to 150 hp at the fly. The standard block is good for somewhere b/w 500-600 hp as I understand it but with aftermarket parts.
Now fast forward to the modded V8's. Don't be too quick to draw a conclusion from them. Check out this youtube vid
http://www.youtube.com/watch?v=FZZWoDweqJk
It's 10 mins long but worth the download. Apart from the twin turbos on this Ford GT the rest is completely stock and yet it produces over 1000 rwhp and 700footpounds of torque!!!!
WTF?!?!? All from a standard GT motor.
The only bad thing ford did was stop producing them!