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This ’94 Buick Roadmaster sits on Impala SS wheels, but the real secret lies under the hood. A former test car at the GM Mesa, Arizona, Desert Proving Grounds, it packs an LS1 Corvette powerplant! You read that correctly, there’s an all-aluminum Gen III Chevy small-block powering this one. Remember, though, that while the mass-production LS1 arrived in 1997, handbuilt LS1 engines were running around in test cars at least three years earlier, and here’s the proof. We didn’t get a chance to lift the hood and search for preproduction castings or neat dead-end stuff, but the exhaust rumble was pure Corvette. Was Buick considering this as a production offering to one-up the LT1-powered ’94 Chevy Impala SS? Unfortunately, no. GM dropped all RWD fullsize cars after 1996, a full year before the showroom arrival of the LS1 V8. So, what we have here is likely a Corvette development car—no, seriously. Carmakers regularly hide new engines and drivetrains in older bodies so they can perform real-world testing.