Every air-cooled Porsche 911 on the market has an engine in it. Far fewer have the engine Porsche put in them. That gap drives the biggest originality swing in the long-hood and impact-bumper market.

The supercharged 6.2-liter LT4 makes 668 hp and 659 lb-ft in the Cadillac CT5-V Blackwing, outmuscling smaller European turbo ...