The one saving grace was Baldwin Chevrolet's parts manager, John Mahler, who worked closely with Rosen to lock in a Chevrolet factory high-performance-parts pipeline connection. Without Mahler's cooperation, the program would've never gotten off the ground. A hot rodder and drag racer, he was also the link for selling the stock engines that were pulled when putting factory-new 427/425 engines in 396/375 cars.
The first Baldwin-Motion Corvettes were part of the Fantastic Five model lineup for 1968. The SS-427 Corvette (coupe: $4,899.95; convertible: $5,099.95) was a Baldwin-Motion badged and dyno-tuned stock vehicle. In the scheme of things, they were heavy on hype and light on performance enhancements; however, Rosen did come up with a Mark III option package (mid-year) of minor engine and chassis modifications that upped the Corvette's performance and came with a written 160 mph top-speed guarantee. Sales of Baldwin-Motion '68 Corvettes were severely hampered by factory fit-and-finish problems (especially leaky T-tops and even battery-related fires).
In 1969 Rosen put a lot of energy into the Corvette program, resulting in a full line of Baldwin-Motion Corvettes. The Sensational Six lineup for 1969 included the dyno-prepped and re-badged SS-427 (coupe: $4,999.95; convertible: $5,199.95), Phase III SS-427 coupe or convertible (Automatic: $6,499.95; Four-Speed: $6,995.85) and eventually, the Phase III GT which could be had with either small- or big-block power. Baldwin-Motion Corvette engine options included aluminum-head L89 tri-power ($350), aluminum-head 12-to-1 L88 ($995.00), and an all-aluminum ZL-1 race engine ($3,000). Phase III GT prices started at $10,500-not exactly chump change in 1969! "I wanted to build the quickest, fastest, and best-handling American GT car for myself, so I started with the best America had to offer," said Joel Rosen. "Once I got into the project, I realized that there would be a market."
The prototype GT was built on a new leftover '68 427/435 coupe in 1969 and powered by a 500hp, blueprinted, Phase III engine fitted with headers, RPO N14 factory outside exhausts (a 1969-only option), Motion Super/Spark CD ignition, finned M/T alloy valve covers,and a 1,050-cfm Holley three-barrel on an alloy high-rise intake. Special shock absorbers, springs, and traction bars were installed to harness the horsepower and insure safe high-speed handling. It is the Phase III GT's styling, however, that truly set it off from both stock and customized period Corvettes. The small notchback window was removed, the inside cavity opened, and a large fastback-style backlight installed. The newly acquired stowage area was fitted with stereo speakers and finished with wall-to-wall carpeting. Like a true GT, there is room for real luggage.
A unique paint treatment (the prototypewas executed in Monza Red with black stripes and trim), polished Le Mans quick-fill gas cap, faired-in headlamps, functionally-scooped Phase III hood, Shark-style functional side vents, flared fender wells, streamlined remote right and left side mirrors, and super-wide slotted alloy wheels shod with Goodyear Polyglas GT tires are key styling cues of the GT. The prototype GT, as well as the first couple of '69 GTs built, did not have the faired-in front headlights or the custom taillights which became standard on the 1970 models.
Rosen knew that his GT would be finished in time to launch the program to both press and the public at the prestigious 1969 International Auto Show held in the long-since-gone Coliseum, then the top show venue in New York City. The project also got a real boost when the head-turning red GT landed on the cover of the August 1969 issue of CARS magazine.