Back before the mighty C6 ZR1 rumbled out of Bowling Green with its supercharged 6.2-liter LS9 V-8 making 638 horsepower and 604 pound-feet of torque, there was a previous king-of-the-hill Corvette that bore the same ZR1 name (though it was hyphenated ZR-1). The C4 ZR-1 saw production from 1990 through 1995 and came with a rather unconventional engine design never before seen powering a Corvette.
The ZR-1’s small-block 350 had dual overhead cams and 32 valves.
Sure, DOHC are a commonplace thing found in engines, but this represented uncharted territory for the Chevy small block that had always used a single cam and pushrods to operate the overhead valves. Luckily, General Motors had acquired Lotus in 1986, and soon after the purchase, engineers with Corvette approached Lotus with their plans of building the world’s fastest production car. Together the UK-based automaker and The General went to work combining the classic V-8 with the modern DOHC design. The result was named the LT5.
Displacing a familiar 5.7-liters, (or 350 cubic inches, depending when you were born) the LT5 engine produced 375 horsepower, which helped push the ZR-1 Vette to 60 in 4.5 seconds and had a top speed of over 180 mph. The power rose to 405 horses when Lotus redesigned the heads and valvetrain for 1993. Those were stellar numbers 20 years ago.
General Motors had one problem, however. They couldn’t handle the extra workload of building the specialized engine. So GM contracted the engines to be built by Mercury Marine,, a company normally associated with boat engines (and no relation to Ford’s Mercury division). Only 6,939 C4 Corvette ZR-1s were ever built, but they created a legend only touched years later by the C6 Corvette ZR1.
As part of Mercury’s 75-year anniversary, the company is remembering this mighty engine, an dhas placed an example on display at its headquartersI.
Click past the jump to read more about the 1990 ZR-1 Corvette Powered By Merc LT5 Engine.