Today, most SUVs are unibody crossovers equipped with small, fuel-efficient engines. But back in the 1990s, during the heyday of General Motors' GMT400 body-on-frame truck and SUV platform, things were done differently. Both Chevrolet and GMC offered their own versions of the heavy-duty 3/4-ton Suburban 2500 with an optional 454ci big-block engine. This was no four-cylinder pushover or six-cylinder commuter — it was the 7.4L V8-powered beast Motor Trend magazine called "the king of towing." And in addition to its towing capacity, it was big enough to carry the whole family in luxurious comfort.