[VIDEO] The Untold Story of the Chevy LT5 DOHC V8: A Forgotten Legend

May 29, 2025

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[VIDEO] The Untold Story of the Chevy LT5 DOHC V8: A Forgotten Legend

One of the biggest surprises to come from GM in regard to the Chevrolet Corvette was the return of the ZR-1 model in 1990. Powering this new American legend was a brand new small-block V8 that offered 375 horsepower initially before getting pumped up to 405 hp in its last three years. While this may seem low in today’s standards, back in 1990 the ZR1 offered 125 hp more than the standard Corvette and it was equal to many of its contemporaries from Porsche, Ferrari, and other sports car manufacturers.

The LT5 engine in the ZR-1 was unlike any previous engine to power the Corvette and it remains as the only engine for Corvettes that wasn’t built by Chevrolet. In the mid-1980s Corvette chief engineer Dave McLellan wanted to build a new American super Vette, and with GMs recent purchase of Lotus Engineering, he leaned on their race-proven engineering team to design the new engine.

Once the engineering was completed, McLellan turned to Mercury Marine in Stillwater, OK to build the new engine. Mercury Marine had a reputation for building high-performance engines for marine use and the LT5 would be constructed at their plant in Wisconsin.

The C4 ZR-1 debuted in 1990 and right out of the gate it set the automotive world on notice that this was a world-class sportscar. One of those highlights include Hall of Fame racer Tommy Morrison who set a 24-hour speed record in the 1990 Corvette ZR-1 with an average speed of 175.885 MPH!

As for the ZR-1, probably its biggest issue holding it back was the overall cost of the car, which was nearly double that over the price of the regular Corvettes in the day which started at $31,979 in 1990. The ZR-1 price came in at $58,995 and it wasn’t just the cost of the engine that pushed the price so high. The ZR-1s body was wider than the standard Corvette and it required wider tires, plus engineers had to beef up many of the parts including brakes and suspension to handle the additional power.

Those first ZR-1s would go on to sell 3,032 in its inaugural year but the program was effectively ended after 1992 due to prices and falling sales. After the 1992 model year, Chevrolet took the total number of LT5 engines remaining and divided by three to offer a total of 448 ZR-1s each in 1993, 1994, and 1995.

Today we see some of the early ZR-1s selling as low as in $20Ks, but their pricing seems to be improving with each new year.

From Engine Legends via YouTube:

The Chevy LT5 DOHC V8 was a forgotten engineering marvel — developed by Lotus, built by Mercury Marine, and powering the Corvette ZR-1 from 1990 to 1995. Despite its innovation and performance, GM quietly discontinued it due to internal politics. In this video, we dive into the full story behind one of GM’s boldest, most misunderstood engines — from its technical brilliance to its lasting legacy.

Source:
Engine Legends / YouTube

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5 COMMENTS

Rob Bessie May 29, 2025 At 11:44 pm

I wasn’t interested in the Corvette, bot a 1991 ZR1 Wow, changed my mind love it thanks Rob
Milo May 30, 2025 At 6:59 am

Had a friend buy a new 1990 and parked it in his basement as an investment for his kids college education. Don’t think it appreciated a lot when he went to sell it considering he would have done better in the casino stock market. My family had a 1990 red Z and it was a beast for that time.
MJ Dart May 30, 2025 At 9:02 am

I at 32 years of age was working for GM in 1986 when I first came across the LT5 in the engineering garage as we called it at Rochester Products Division. After 5 pm we would occasionally wander through the area looking at “neat stuff” that was being developed. We came across something under a small tarp cover. I pulled it back an there it was, the LT5 in all its glory. Keep in mind the 80’s for the most part had been pathetic in how pitiful performance was in those early years. I was astounded at what I saw in that engine. Rochester devleoped the intake and fuel injection system the LT5 featured. Two injectors per cylinder I saw and what looked to be overhead cams, wow! My co-worker Tony, then in his mid 60’s saw my reaction and said “is this really good”? I reponded this is incredible!!! Of course we realized we could never speak openly about what we saw as this was a very secret area we were in, but boy was that an experience I’ve never forgotten.
Bob in FL May 31, 2025 At 12:06 pm

When these high dollar, overly complicated cars showed up at Lapeer International Raceway, we were regularly knocking them off with inexpensive, simple pushrod, stroked 350-383 small blocks in our street driven C3s. Those were some fun and satisfying memories. Good old fashioned hot rodding putting the white leather loafer, country club poser show-offs in their place… I think the primary reason that the LT5 existed was because modified 1986-1987 Grand Nationals and 1989 Pontiac V6 turbo trans ams were embarrassing Corvettes back then. Glad that Corvette has finally caught on to what Buick was doing in the 80s. I plan to add a ZR1 to my GN and TTA GM turbocharged car collection. I have to get in line behind the Sports Athletes, Celebrities and Corporation Executives of course. Probably will take a year or two. But buying the first year of production is never a good idea when ANY new powertrain design comes out. Patience pays off with better quality and lower prices.
Richard Cunningham May 31, 2025 At 1:05 pm

I believe the LT5 was machined and assembled by Mercury Marine in Stillwater, Oklahoma, not in Wisconsin as stated in the video.