Page 1 of 2 Next >> Progressing through the various classes during the 1980s, privateer racer Jim Miller stepped up to IMSA GTP in 1989. He quickly discovered that his 'off-the-shelve' Chevrolet-engined Spice was no match for the works Nissans and Toyotas. To bridge the gap, Miller first asked engineer Bob Riley to upgrade his Spice ahead of the 1990 season and then commissioned Riley to design a new car from scratch. Tasked to construct the GTP machine was Gary Pratt formerly of Protofab, which had developed the Riley-designed Corvette Trans-Am car previously raced by Miller.
Riley had already been walking around with the design for a mid-engined GTP car for quite some time but until Miller approached him had found no willing partners. Downforce was the key word in IMSA racing, more specifically ground-effect downforce generated by massive tunnels in the floor. Accordingly, Riley designed the new GTP car to have the largest underbody permitted by the regulations. The GTP machine boasted a carbon-fibre composite monocoque with in-board suspension front and rear to free up even more room for the tunnels. It was clothed in an unusually blunt body with slab sides.
Originally, Miller had intended the car to be powered by a development of Judd's V10 engine, which was presumed to be capable of upwards of 1,000 bhp. The IMSA regulations, however, favoured stock block engines over the more exotic purpose-built engines. This prompted Miller to turn to his longtime supplier General Motors for a tried and trusted small block V8. Displacing just under 6.5 litre, the Chevrolet engine was further developed by Katech and equipped with the latest engined management system supplied directly by General Motors. Good for around 800 bhp, the small-block V8 was mated to a five-speed Hewland gearbox. Page 1 of 2 Next >>