Block strength. It's the only two words that jump out in my mind. Love them or hate them, ugly or not, the engines of recent muscle car years offer block strength. Our old iron blocks are at risk when pushing the HP close to 4 digits. Seems the new gen blocks of Ford, GM, or Mopar can handle HP well into the 4 digits. Big Boost, Big NOS systems, doesn't matter with new gen blocks. They make big HP. Street cars that can run 4 second 1/8 mile and 7 second 1/4 mile seem to be less rare these days. Who is competing with factory old iron?