The TR7 was characterized by its "wedge" shape, which was commonly advertised as: "The Shape of Things to Come", and by a curved line in the bodywork sweeping down from the door area to the rear of the car. The design was penned by Harris Mann who also designed the wedge-shaped Leyland Princess. The car had an overall length of 160 inches (406 cm), width of 66 inches (168 cm), wheelbase of 85 inches (216 cm) and height of 49.5 inches (126 cm). The coupé had a kerbside weight of 2205 pounds (1000 kg). During development, the TR7 was referred to by the code name "Bullet".
Power was provided by a 105 bhp (78 kW) (92 bhp (69 kW) in the North American version) 1998 cc 8-valve four-cylinder engine which shared the same basic design as the Triumph Dolomite Sprint engine mounted in-line at the front of the car. There were plans to directly use the Sprint engine 127 bhp (95 kW) in the TR7 and at least 25 pre-production cars were made in 1977 using the 1978 model year bodyshell. This model was getting ready for full production until the closure of the Speke Plant.
These cars, of which several still exist in the UK, can be identified by a different chassis number to the production 8-valve model. Drive was to the rear wheels via a four-speed gearbox initially with optional five-speed manual gearbox or three-speed automatic from 1976.
The front independent suspension used coil spring and damper struts and lower single link at the front, and at the rear was a four link system again with coil springs. There were front and rear anti roll bars, with disc brakes at the front and drums at the rear.