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. This ’94 Buick Roadmaster sits on Impala SS wheels, but the real secret lies under the hoo It's been a few years since GM teetered on the edge of financial abyss. Fortunately, the General is back and perhaps stronger than at any time in recent history. During the '09 Barrett-Jackson Collector Car Auction in Palm Beach, Florida, GM decided to offer a selection of items from its in-house vehicle archive/museum, the GM Heritage Collection. While some incorrectly predicted this was a desperate, fire-sale move intended to keep the lights on a few minutes longer, the fact is, GM regularly skims cars off the top to make room for new additions. For the spring 2009 Florida auction, somebody at GM had the foresight to ask, "Why do we crush our engineering mule cars and other oddball stuff? Why not let them out into the world so collectors can appreciate and preserve them?" Naturally, most of these vehicles carried scrap titles—to prevent their use on any public road...ever. And so it was as dozens upon dozens of former GM Heritage Collection vehicles were released into extremely grateful private hands at auction. Though some of the offerings were little more than dolled-up show cars meant to be seen by the public, there were also many former top-secret critters scampering away to safety. Let's have a look at these refugees from the crusher. The sight of any ’86 Pontiac 2+2 is rare enough, but one bearing a VIN marked EX4788 and with a GM-provided description calling it an ’85 model? Now that’s pretty wild. Though Pontiac did build 1,118 of these aerodynamically enhanced GPs for NASCAR homologation in 1986, this one’s a preproduction prototype. Though it carries the same sleepy 165hp 305 as any other V8 GP (sorry, no LS1). The real news is at the back of the car. The sight of any ’86 Pontiac 2+2 is rare enough, but one bearing a VIN marked EX4788 and w Notice something missing? Production 2+2s wear a huge glass bubble of a backlite that’s designed specifically to slip through the air at 200-mph NASCAR race speeds. The problem was that the one-piece glass was so long, Pontiac had to compensate with a mail slot for a trunk lid. Also, each installation called for a ton of hand fitment work that wasn’t assembly-line friendly. Not here. Notice how the trunk lid is fullsize to allow complete access—also note the 270-degree duckbill spoiler. Rendered in plastic, this molded trunk lid was very likely considered a wind tunnel alternative to the glass bubble layout that ended up in production. With this structure, building the 2+2 wouldn’t need any extra bodywork other than substituting this simple trunk lid, and customers couldn’t complain about the tiny trunk opening. That said, the failure of this configuration to reach production is likely based on its failure to perform as well as the glass bubble in the wind tunnel. Truth be told, we’re glad this deal died. Notice something missing? Production 2+2s wear a huge glass bubble of a backlite that’s de Ugh, an ’80 Chevy Citation X/11. Few sights conjure memories of the bad old days like this thing. No 135hp, HO-660 V6 and fiberglass cold-air hood is ever going to make a Citation cool. But what if Chevy stuck two engines in a Citation? That’d change things, right? Well say hello to GM Engineering’s “push me/pull me” Corvette prototype. Corvette? Yes, Corvette. Masterminded by GM engineer Richard Balsley (who ran a ’56 Ford with twin 312 Y-blocks on Woodward as a kid), this is an exploration into a possible twin-engine configuration to keep the Corvette competitive in a post-V8 world. Ugh, an ’80 Chevy Citation X/11. Few sights conjure memories of the bad old days like this This is normally a front-engine, front-wheel-drive platform, but Balsley mounted another power- train cradle under the back of this special all-wheel-drive Citation. He stroked each 2.8 mill to 3.1 liters and added forged and billet guts for a combined total of nearly 600 hp. Here’s a peek at the handbuilt rear suspension. The VIN reads 15X0169, so you can forget about registering this one for street use—unless you own an automobile factory and have manufacturer’s plates available. Didn’t think so. This is normally a front-engine, front-wheel-drive platform, but Balsley mounted another p Inside, note the double-vision gauge setup to monitor the coolant temp, oil pressure, and alternator function of each engine. If GM had canceled all further V8 production in 1980 (as was considered), this is one way the Corvette team might have allowed future Vettes to have world-class performance—and acceptable fuel economy (the Citation body was just a mule to sort things out). In the end, saner minds prevailed (hello 5.7 Cross Fire, TPI, LT1, LT4, LT5, LS1, LS3, LS9, and so on). That didn’t stop Balsley from revisiting Woodward in this thing a few times. He admits, “We liked to dust dentists on Woodward Avenue in their Turbo Porsches.” Inside, note the double-vision gauge setup to monitor the coolant temp, oil pressure, and A total of 23,330 Corvettes were built in 1994. What makes this one special is that is bears VIN 1G1YY22P4R500001. See all those zeroes? Yep, this is the first regular- production coupe built in 1994 (excluding preproduction prototypes), and that’s cool. But it’s also an example of GM’s continued philanthropy. After serving duty as a GM test car, it was donated to Arapahoe Community College for engineering students to work on. GM was contacted after students discovered the low VIN, then the car went to the National Corvette Museum for display. Any Arapahoe grads out there remember this car? A total of 23,330 Corvettes were built in 1994. What makes this one special is that is bea To thwart those who might look a gift horse in the mouth, GM placed these stern warning and disclaimer stickers on the windshield. Get out your magnifying glass and don’t cry when you get to the part that reads, “Upon completion of your use of this vehicle, it must be scrapped (completely destroyed) by you.” Yikes! Fortunately it’s in the hands of a caring Corvette collector who (we hope) will refrain from removing the dead-man-walking stickers. To thwart those who might look a gift horse in the mouth, GM placed these stern warning an Let’s close things out with this amazing creature. Akin to buying a UFO from the CIA (the truth is out there), some lucky bidder scored this C6 Corvette preproduction beta test mule. During testing, these cars often go out on public roads as early as a full year before official new-car announcement time, so padded vinyl cladding is applied to disguise exact styling cues—like the front fascia bra and crude cover affixed to obscure the front fender scallop detail. Note how the Velcro-backed patches approximate the look of the pop-up headlamp pods used on the C5 Corvette. Let’s close things out with this amazing creature. Akin to buying a UFO from the CIA (the In reality, the patches must be removed for nighttime test duty since this mule—like all production C6 Corvettes—was the first Corvette model since 1962 with exposed nonretractable headlamps. Lifting the flap exposes what appear to be production-equivalent projector beam headlamps. There’s a GM Milford Proving Grounds sticker on the windshield. Man, if only this thing could talk! In reality, the patches must be removed for nighttime test duty since this mule—like all p Though some mules wear simple, stamped, metal VIN tags, this one has what appears to be a normal VIN plate with the usual etched characters and UPC bar coding, until you notice the suffix that reads EX—for experimental. Going further, while a regular ’05 Corvette coupe VIN would read 1G1YY24U855100001, this one reads 1G1YY24UX5X7120EX. Yep, more Xs to confound the DMV computer. The letter U in the eighth spot is shared with production Corvettes and signifies the new-for-’05 6.0L, 400hp LS2 mill. Historically, cars like this just don’t survive or ever wind up in private hands. But thanks to the open-mindedness of the GM Heritage Collection, this, and several other noteworthy engineering test cars, will live on. Wouldn’t you just love to show one of these things off to your friends? Just don’t try and get license plates—it ain’t gonna happen. Though some mules wear simple, stamped, metal VIN tags, this one has what appears to be a Groovy Factoids • If you're digging the C4 Corvette's scene, you must read Corvette from the Inside, former Corvette Chief Engineer Dave McLellan's tell-all book on how the C4 was developed. It's from Bentley Publishers (BentleyPublishers.com), or score a copy from Amazon.com. • As you read this, hundreds of engineers throughout Detroit are working on the top performance cars of 2015. No kidding. Conversely, what you buy new today was designed a few years ago. A Detroit insider once lamented to us: "I hate buying new cars. From my vantage point, they're already a few years old!" By Steve Magnante Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!