This V8 Is Chevy's Best Kept Secret

Throughout the history of General Motors, the Bowtie brand in specific has given us some of the most popular and versatile V8s of all time. From the original small block Chevy to the modern LS platform, nearly everywhere you turn at a car show, you're going to see one of those engines. They are reliable, affordable, and can make gobs of power. However, there is one problem with them. It's that they often overshadow the other great engines that General Motors built over the years. And one of those V8s that we often overlook might just be one of Chevy's greatest engines ever. Yet, even though this was a Chevy engine, it wouldn't have been possible without the help of Lotus and Mercury Marine. With four overhead cams and an aluminum block, this original 5.7 liter LT5 V8 is one of GM's best kept secrets. And its creation story is fascinating. Now, the plotline of this engine starts back in the early 1980s. Around this time, the Corvette needed a refresh from the aging C3 platform, which was really on its last legs. The solution to this, as we all know, was what became the C4 Corvette. An 80s reimagination of the Corvette that was brought in with new tech, new style, and a whole lot of new engineering. The C4 Corvette was offered with a myriad of 5.7 liter V8s, from the L98 to the LT1 and LT4 motors. The C4 got progressively faster over the years, but with the performance cars of Europe and Japan seemingly progressing faster and faster each year, the base model C4 wasn't going to cut it anymore as the pinnacle of General Motors might. They needed a king of the hill to reassert the Corvette's dominance on a world stage. Lloyd Roos, who was the head of GM at the time, greenlit this project to create a new super vet, which would become the C4 ZR1. Now, the ZR1 chassis itself had its own host of improvements that made it significantly better than a regular C4, but the ZR1 wouldn't even be a ZR1 without what lied under its hood, which was the all-new LT5. Which, unfortunately or fortunately, we have to thank the Brits for. Because if General Motors had not purchased a little car manufacturer called Lotus in 1986, this new LT5 motor would have never been made. With the General Motors acquisition of Lotus came all the technological know-how that they utilized in Formula 1, and what came with Lotus was a man by the name of Tony Rudd, and he would be the key to this puzzle. Tony Rudd was an engineer at Lotus who, right before the GM acquisition, was working on the Lotus Aetna concept. Meant to be a new flagship car for the Lotus brand, the Aetna also needed a new flagship engine. Tony was the man tasked with creating a new V8 for Lotus that could make 320 horsepower and over 300 foot-pounds of torque. What he would create was the all-aluminum, dual overhead cam, 4-liter, Type 909 V8. This cutting-edge new motor was destined for greatness, but upon the change of ownership of Lotus, it never found its way into any real cars. All was not lost though, because GM clearly saw the potential in a dual overhead cam setup for a Corvette application. A tune-port injected 5.7-liter Corvette in the mid-80s made around 230-240 horsepower. The Lotus engine made nearly 100 horsepower more, and only had around 70% of the displacement. Now, one would think that GM could have just taken the Lotus 909 V8 and shoved it into the Corvette, and voila. But unfortunately, that motor wouldn't quite fit in the Vette. Plus, the Type 909 engine shared zero parts compatibility with any GM products, which wouldn't have made the bean counters at General Motors very happy. So, the solution was a compromise. Take the existing L98 tune-port injection motor from the Corvette and re-engineer it to be compatible with the new valve train based on the Lotus Type 909 engine. It sounds simple, but it was a much more arduous process than that. First, the L98 had to be completely recast from an iron block to an aluminum block for this application to keep the front end of the new ZR1 light. This new aluminum block was actually two pieces, an upper case for the cylinders and a lower case for the crankshaft. Oh, and this new wasn't actually assembled in a GM factory, or a Lotus factory for that matter. Mercury Marine, the company that makes boat engines, actually were the ones that made the blocks. They had a reputation for offering some of the highest quality marine engines out there, so GM was comfortable allowing them to cast their new blocks for the C4 ZR1. And speaking of well-built, if you're anything like me and you spend a ton of time at your desk, then you need to check out today's video sponsor, Flexispot. Flexispot's range of adjustable desks are built to last, and to make you as productive as possible. The adjustable heights of these desks can help alleviate neck and lumbar pain by giving you the exact position you need at a given time, rather than being all cramped up and hunched over. And get this, the Flexispot desk that I'm sitting on right now is rated to hold 560 pounds. For reference, that's what a small block Ford 289 weighs. And even with that much weight on it, these desks are super stable. Guys, I'm 185 pounds right now. I'm sitting on this desk, no problem, it's not moving, it's not wobbling, everything is good to go, and I'm on a carpeted floor. Compared to my other desk here, which is the old desk I used to use for all of my editing and all of my work, it's next to me here. With just a little bit of hand pressure on this, this entire thing is shaking. The books are moving, everything's going crazy. The Flexispot desk is way better, and the Flexispot E7 desk right here isn't just for your office work. This is perfect for your garage or workshop. With a range of sizes available, this one here happens to be a 48 by 30, but they make them as wide as 72 inches, and they can still support serious weight at that size. Literally throw whatever project you have onto this desk here and get to work. In my case, I have this big thing of dynamite. I'm just going to put it here on the desk, and we're good to go. I can literally sit down on the desk, on top of the dynamite, go to the switchboard here, and raise it up no problem. Here we are. It's that simple, and it's still totally stable, even as we go up in different heights. Backed by a 15-year warranty, these Flexispot desks are the real deal, as are their Black Friday deals. Flexispot also offers a range of home appliances, including air purifiers and vacuum cleaners. And during Black Friday, if you purchase any Flexispot desk or chair, you can get some of the small home appliances for as little as $89.99. For Black Friday, you can enjoy discounts of up to 65% at Flexispot. You also have the chance to win free orders during this period as well. Use my code YTE7P50 to get an additional discount of $50 on the E7 standing desk. So don't miss this opportunity, as prices are as low as they're going to be for Black Friday. Thank you Flexispot, and now, back to the video. With the LT5 motor, there were some other changes from the base L98, particularly when it came to the bore and stroke. For the LT5, they decreased the bore from 4 inches to 3.9 inches, and they also increased the stroke up to 3.66 inches, which was an increase of just under 0.2 inches from the regular L98. The compression ratio was also cranked up to 11 to 1, thanks to a new set of dished pistons. The heads were fully redesigned to now accommodate the dual overhead cams on each cylinder bank, which were connected via double roller timing chains, which were kept in check by their timing chain guides and hydraulic tensioners. With two intake valves and two exhaust valves per cylinder, plus a total of 16 intake runners, the LT5 was ready to breathe, and it could now accommodate a power curve much higher in the rev range. The stock L98 made peak power at 4,000 RPM. The LT5 would peak at over 6,000 RPM, which was a staggering difference. Twin fuel pumps and 16 total fuel injectors were fitted to the LT5 as well, doubling that which would have come on a standard L98. When all was said and done, the first LT5 was shipped in the ZR1 in 1990, and it made a whopping 375 horsepower and 370 foot pounds of torque. Singing all the way to 7,000 RPM, for 1990 this Corvette might as well have been a rocket ship, and it was neck and neck power-wise with the Ferrari V12 Testarossa. And fitted to an improved C4 Corvette chassis with better brakes and better suspension components, the new C4 ZR1 was an absolute weapon, thanks largely to that LT5. It was really almost America's first supercar if you take the performance on paper of the C4 ZR1 and compare it to all the contemporary offerings from other brands. It doesn't get enough credit, the C4 ZR1 was pretty damn fast for 1990, and in 1993, the LT5 in the ZR1 got a revised valve train and exhaust to help bump peak power to 405 horsepower, which was the final form of this engine that we got in any production car. Because by 1996, the ZR1 Corvette was gone, as was the C4, and unfortunately, so was the need for the LT5. Really though, if we peel back the curtain a little further, we could see why the LT5 actually got axed, and it really wasn't by any fault of its own. The engine was fantastic, it was rev-happy, made great power for the time, and it even had ECU programming where it could be run in economy mode at just 200 horsepower with injectors and intake ports closed off to improve highway mileage. The issue came from other Corvettes in the C4 lineup. By the time the ZR1 had come out, new power plants were also beginning to be fitted to the base model C4s, like the LT1, and finally the LT4. The L98 made a max of 245 horsepower stock, so when the ZR1 first came out, 130 horsepower above that, it was a no-brainer proposition. But as the C4 got the 300 horsepower LT1, and even the 330 horsepower LT4, the gap between the ZR1 and other Corvettes narrowed, which hurt the value proposition of the C4 ZR1, considering the C4 ZR1 was nearly double the MSRP of a base model Corvette. General Motors also didn't like the fact that all of the ZR1 LT5s were actually manufactured not in-house, but by Mercury Marine and then shipped out to be fitted into the cars, which made their production rather expensive and cumbersome. 1997 brought the C5 Corvette to the market, and the LS motor with it. But even the mighty C5 Z06, which came with the LS6 engine in 2001, was only able to match the power output of the LT5 from the ZR1 that came out 10 years prior. The dual overhead cam LT5 had plenty more life to give in it as an engine. Even GM thought so, and apparently was working on an updated 3rd generation motor when the came down to kill the project, a motor that would have made near 500 horsepower. But because of the economies of scale that GM could get with the newer and cheaper to produce LS engine, the LT5 was cast away. Lotus, however, would give the LT5 engine a final crack within the Elise GT1 race car, designed to compete with the likes of the Mercedes CLK GTR, McLaren F1, and Porsche 911 GT1. The Lotus Elise GT1 was an attempt for Lotus to compete in the highest echelon of racing against some of the world's most high-tech cars. They would just have to do it on a shoestring budget. It would heavily modify the current Lotus Elise chassis to create a race-ready version, which was powered by either a twin-turbocharged 3.5L Lotus V8 or an overhauled version of the 5.7L Corvette LT5. This LT5, with its higher compression, freer-flowing exhaust, and host of other internal overhauls, made a whopping 600 horsepower. And funny enough, of the 7 Lotus Elise GT1 race cars built, the only ones to be used by the actual factory Lotus team would be fitted with the LT5, which certainly says something since Lotus was more confident in that powerplant than their own. Production car-wise, the LT5 was only ever fitted in the C4 ZR1 cars, which means that the 6,900 ZR1s that were sold basically represent all the LT5s ever produced, minus some factory replacement motors and the handful of engines used in race cars. But with their limited production run, GM eventually stopped carrying and making factory replacement parts for these engines altogether. As a result, many ZR1s sit around today with super low mileage because people are holding onto them as collectibles, partially because of their rarity, and the other part of the equation is that the lack of engine part support makes people unlikely to beat on them and drive them the way they should be, for the fear of incurring some kind of irreparable damage. The silver lining to this though is that now with the C8 Z06 Corvette out, we know what the LT5 coulda became. The new Z06 motor is a 5.5L flat-plane crank dual overhead cam V8, which I like to think of as the late-stage LT5 successor. We just never ended up getting the ones that would've came in the years between, but to see the first dual overhead cam V8 vet, and what the ultimate form of it looks like some 30 years later, is a pretty awesome way to close out the story. Now let me know in the comments down below if you share in the sentiment that the LT5 is one of the best-kept secrets when it comes to V8s, or if you think it's an overcomplicated and overpriced boat anchor. I for one think it's an awesome motor. And as always, thank you all for watching another video. Please make sure to like, share, and subscribe, it really helps me out. But otherwise, until next time Enthusiasts!