1984 (1985 season) International Race of Champions CamaroThe next image car for the third generation Camaro was the International Race of Champions race cars seen in 1984 on the course. After a three-year hiatus, the race had been reinstated–and was again using Camaros. (Camaros had previously been used in the IROC competition from 1975 through 1980, when the race was cancelled until resuming in 1984.) Literature from 1984 alerted people to the fact that what they were seeing was a thinly veiled version of the updated 1985 Camaro.

1984 (1985 season) International Race of Champions CamaroInterestingly, in speaking about the race car’s design, Mr. Palmer had this to say, “That was a fast job–timewise, I mean. We styled the car over the Christmas break. Obviously, the aerodynamic considerations were a high priority, but we had to maintain the image. The IROC race cars appeared with a more rounded front fascia than the ’82-84 Camaro, but they still were obviously Z28s.”

A fact that may surprise many is which was car was imitating the looks of the other. Mr. Palmer clarifies, “To the public at large, the ’85 Z28 and IROC-Z street models were modeled after the IROC race vehicles, but in reality the opposite was true. We actually sent one of our ace designers, Randy Wittine, [to where] the cars were being done to ensure they would have the look of the ’85 Z28 and IROC-Z.”

1985 Camaro IROC-ZWile not a race car, pace car or even a show car, the fourth third-generation Camaro considered by Chevrolet to be an “image car” was the production IROC-Z. Mr. Palmer explains that, “The IROC is a kind of, let’s say, Z28 plus that anybody able to cough up a few extra bucks can buy.”

In my opinion, this model represented the apex of the third generation’s design. Everything seemed perfectly in place.

Alright already. So how about the GTZ, you ask? Keep reading.

SEMA, an excuse for cool stuff
Prior to that historical diversion, we left off with the dilemma facing auto manufacturers, particularly in reference to performance models. The dilemma they were facing was which direction to go with their new powerplants. Both Ford’s Mustang and GM’s F-body twins (Camaro and Firebird) were being seriously considered for front-wheel-drive conversion come the new model, sometime in the late 1980s (more on that in a forthcoming post). By 1985, at least at GM, that work was well underway.

GM was not prepared to show off their design progress on those FWD concepts (code named GM-80) but they did have something they wanted to exhibit, and they felt it was important to get a sense of how the market would react. It was a modified V-6 engine being considered for use in future F-bodies.

1985 Chevrolet Camaro GTZ SEMA wheelsThus, the 1985 Chevrolet Camaro GTZ show car was commissioned and its first destination was to be the Specialty Equipment Manufacturers Association, otherwise referred to by its acronym, SEMA. That location wasn’t a matter of happenstance or coincidental timing.

GM and Chevrolet were keenly aware that the small-block V-8 was incredibly popular and the foundation of Chevy’s performance machines. GM was treading lightly because depending on which way they proceeded with their cylinder-count dilemma it could have deep ramifications. After all, generations of tuners were accustomed to the small-block. So, the Special Products Group, headed by Herb Fishel, chose a direction that could be considered a happy middle ground between the tried-and-true small-block and a smaller, V-6 engine.

Faced with a choice between two V-6 powerplants to use as a starting point, Chevy’s 2.8-liter or their 4.3-liter, they chose the latter. The choice was, in large part, due to the familiarity tuners would encounter with the 4.3. As with Chevy’s small-block V-8s, the 4.3 V-6 was a 90-degree (opposed to the 2.8’s 60-degree) design and, generally speaking, it amounted to a 350 cubic-inch V-8, sans two cylinders.

John Pierce, then-special projects engineer, stated the importance of doing it right for the SEMA show, “Remember, the SEMA show is put on by the manufacturer’s of most of the hot-rod componentry sold in the United States, and those boys have made their fortunes on the of the Chevy small block V-8.” The advantage of using the 4.3? Mr. Pierce continues, “[…] many of the internal bits of the 4.3-liter V-6 are common with the 350 cubic-inch version of the small-block eight.”

Chevrolet had been utilizing a version of the 4.3 as the standard engine in the large Caprice Classic. In that guise it made 130 HP, at 3600 RPM.

For the GTZ, the block was cast in aluminum with aluminum splayed-valve heads. A prototype, air-mass sensing port injection system using a customized intake plenum was installed. Further modifications using parts from the performance parts bin included a beefed up crank and stronger rods. The engine’s ignition system was a distributorless design.

The GTZ’s modified engine was referred to as the 4.3 XPV-6 and cranked out 230 HP which was more than the currently offered production 5.0-liter V-8. The brakes were standard Camaro fare up front and used the production version’s optional discs in the back. Shifting was accomplished with a Borg-Warner T-5 manual gearbox, also optional on the production Camaro.

Even though the engine was the centerpiece, the wrapper kind of stole the show.

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