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History of the Black Widow ZR-1 Corvettes

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The following article is a personal account of the Black Widow LT5 Engine program by Jim Van Dorn, owner of Auto Masters located in Palm Desert, CA.

by Jim Van Dorn
February 10, 1998

In the early days of the LT5 program, MerCruiser and Lotus continued to develop the LT5 after the production configuration was certified and finalized. They produced several LT5s for racing (Daytona with Morrison, Baker, etc). With all of the LT5s in production, it would be prudent to assume they would want to readily identify these non-production engines so that a mistake would not occur. Rather than painting a big red "X" on them, they decided to use a black wrinkle finish powder coat they had available.

Black Widow LT5 EngineLater, in maybe 1992, Doug Rippie spoke with Gary Cline [Senior Manufacturing Engineer- MerCruiser] regarding the possibility of producing a special higher horsepower version of the LT5, specifically, a 475 hp version. The program was blessed by all including Chevrolet and MerCruiser and it was decided that again, these higher horsepower versions would be identified by the black wrinkle finish. Rippie took the engines out of the customer's cars and sent the necessary components to MerCruiser where they were modified and painted.

I had the occasion to send my car to Rippie for this conversion and in fact, my engine was in the process of the modifications at MerCruiser when the word came down that the LT5 program was to be terminated. My engine, for the "Weekndr" [JVD's personal ZR-1], was #8 and the last of these black motors...well...almost.

After I received my car back, I noticed the black engines and red wires reminded me of a Black Widow's distinctive markings, and I nicknamed these engines the "Black Widows". The name stuck and when Tony Young was writing the "Heart of the Beast" [book], he called numerous times in his research of the history of the LT5/ZR-1s and one of those phone calls was in reference to the Black Widow engines. (see Heart of the Beast, page 174-175).

Among other black engine stories are the following:

In 1992, the LT5 Gang at MerCruiser offered to paint the engines in all 40 th Anniversary ZR-1s black as part of the 40 th [Anniversary] package. Although this was offered at no additional charge, to GM, the folks at GM, already knowing the inevitable, decided against bringing more attention to the ZR-1. The program was denied.

In 1993, Rippie and I came up with the idea to offer the black engines as a factory option, similar to the [RPO B2K] Callaway option of the '80s. We soon found that the folks at Lotus had begun to develop their own 475 hp version of the LT5 which they offered GM for production in all 1995 models which were to be the last produced. one of the thoughts behind this special high horsepower engine was they already knew the Viper was coming in '95-'96 at 450 hp and they wanted the King to stand on its own for years to come. We again chose a black powder coat and in fact, I have the prototype cam cover, complete with gold emblem, on the shelf here in my office. AGain, due tot he fact that the ZR-1 needed to be gone by the time the C5 got here, the program was squashed by GM.

Now...in the above, I said "almost" the last black engine...

Our Street Skinner package is based on the same principles used in the black motors of old. During the course of the engine enhancement of our own Mr. [Doug] Johnson's beat up old '90 ZR-1, I had the occasion to speak to a member of the original LT5 gang. In that conversation, I asked if there happened to be any remnants of that old black powder paint left laying around. As luck may have it, a small amount of that very same powder was found. Enough to do just one more engine...

Mr Johnson is the owner of the last "black" LT5 engine to come from within MerCruiser.


The following information comes from "Meet Doug" on the Doug Rippie Motorsports web site.

The Black Widow Project

Click on picture for enlarged image.In December 1992, at the 40th Anniversary Corvette Show in Palm Springs, California, Doug met Gary Cline the LT-5 Project Engineer for MerCruiser. At first they chatted. Then, as the evening grew longer, they started talking about ideas. Rippie listened and thought. He asked, "Whatta you think?" and "What if?" more than a few times. They agreed that the best idea of all would be to do more than talk.

"I think anyone who’s tops in his field wants to see what he’s created be all it can be," says Rippie. Cline, other MerCruiser LT-5 project engineers, and Lotus engineers who were involved in the project knew their engine was capable of higher performance than it had powering the ZR-1 Corvette. Doug Rippie was a kindred spirit. It was decided to work with him to produce a special LT-5 engine, the DRZ-500, also known as the "Black Engine" because each of the DRZ-500 engines produced was painted with special black paint and the "Black Widow" engine, from the nickname given by Jim Van Dorn to the eight DRM-converted ZR-1 Corvettes that are powered by DRZ-500 engines, one of which he owns.

The DRZ-500 engine resulted from the cooperative effort of Rippie, Cline and other MerCruiser engineers, Graham Behm of Lotus Engineering in England and Tim Holland of Lotus Engineering USA, and Chevrolet’s blessing. There were four versions:

405 horsepower DRZ-500s, 1990-92 model LT-5s updated to 1993 specifications
450 horsepower DRZ-500s, 1993 LT-5s, 50-state-legal
475 horsepower DRZ-500s, 50-state-legal
525 horsepower DRZ-500, a full race version

Special precision machining and porting, camshaft installation, and black painting was done at MerCruiser. DRM did the disassembly and assembly as well as calibration and emissions certification. There were only eight DRZ-500 engines produced, between March and July 1993, because production of the LT-5 was due to end in November of that year and time ran out to produce more than eight.

Click on picture for enlarged image.The "Black Widow" ZR-1 s powered by DRZ-500 engines are more than just an examples of why Rippie and his small band of midnight oil-burners are capable of producing. They formed a bridge between the race track and the street for DRM. High performance to Rippie is not only high horsepower. It is a finely balanced combination of power, handling and braking. To match the power of the DRZ-500, Rippie could do nothing less than develop suspension and brake packages for the ZR-1 Corvette with equally outstanding performance characteristics. The results, rave reviews by everybody who’s driven one converted by DRM to be a "Black Widow."

Since the last "Black Widow" was completed, DRM has gone on to convert ZR-1s into even more spectacular performers. The current top-of-the-line is the DRM 600 Corvette ZR-1, a direct descendent of the Black Widows powered by a 385 cubic inch 550hp engine that takes a mere 3.9 seconds to reach 60mph and just 19 seconds to 150mph covering the quarter-mile in only 11.8 seconds at 122mph. ZR-1 s converted to DRM 500 specifications, similar to the Black Widows, are powered by LT-5 engines ranging from 415hp to 475hp.

In August of 1996 a very special DRM LT-5 motor was tested in the desert at over 600 horsepower which produced 493 horsepower to the rear wheels. Everything learned by DRM has been adapted for application to all the ZR-1, LS-1, LT1/LT4 and L98 Corvettes it converts and to Camaros and Impala SSs. "Can you make me one of these.." resulted in a custom built tube frame chassis Corvette using lightweight stock components; "We know you’re the expert..." brings LT-5 factory authorized motor repairs to the DRM shop; and "Our new product would be perfect if we had your input..." creates more R & D opportunities for the Doug Rippie Motorsports team. When customers, vendors and competitors speak...Doug Rippie listens.

Everyone who’s ever driven a DRM-converted Corvette knows they run on the road like DRM race cars run on the track, up front. You only have to press the throttle pedal down or dive into a corner at speed to know that a DRM-converted Corvette is a precision driving machine....A car that responds almost intuitively and makes driving a uniquely exhilarating experience.

 Additional References
·  "Double-Thread Vette: Spinning Wheels and Ripping Rocks at 180 MPH", Motor Trend, April 1994, pp. 82-86
·  ZR-1 Performance Review

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