When it comes to the modern-day straight-six, the M 256 is a force to be reckoned with. That's the designation for the most powerful straight-six engine in the current Mercedes-Benz lineup, which also ...

You just put your new crate engine together and your adrenaline is pumping. Pump the throttle, turn the key, and… the thing runs like a total dog. It idles fine, but as soon as you step on the ...