For export to the US market, Triumph created a much more powerful Triumph TR8 model in 1977/78, which was a TR7 with a 3.5 L Rover V8 engine. While some genuine TR8 models stayed in Britain, these examples are exceedingly rare. Most TR8s went to the US, where they did not fare well, owing to Triumph's poor build quality at the time and the unusually strong pound, which peaked at around $2.40 by 1980, making Triumphs fairly expensive compared to competitors. The TR8 was only launched as a convertible (DHC) model. However, about 400 hard-top (FHC) TR8s were produced at Speke and Canley, as these were needed (possibly with some TR7s converted by BL to TR8 specification) for the Group 4 homologation of the TR7V8 rally car. Spider In 1980, a limited edition version of the TR7 Drophead was launched for the US market by the US importer. Called the "TR7 Spider", it was available only in "maraschino black", with reflective red striping and badging plus black interior trim. Alloy wheels and the steering wheel from the TR8 were fitted, along with a "pewter grey" carpet and grey striped upholstery. Based on an exhaustive inventory of the factory build cards at the British Heritage Motor Centre archives, it has been confirmed that 1,070 carburetted Spiders were built at the Solihull factory with an additional 548 fuel-injected (Bosch L-jetronic) Spiders built specifically for California. VIN numbers for Spiders run from 400301 to 401918 overall and for the fuel-injected version from 401374 to 401918. All the Spider-specific equipment was installed at the factory, with the exception of the radio-cassette, which was stored in the boot and installed at the port of entry. Grinnall Slightly less than a decade after the original TR7 ceased production, another British manufacturer, Grinnall Specialist Cars modified existed TR7 and TR8 cars. TR7 cars were upgraded with TR8 subframes and dash. They then installed V8 engines (optionally bored to larger capacities), and other parts like suspension, gearbox and brakes from the Rover SD1. The front and rear wings were widened to match the SD1 axles and suspension. 350 convertible cars were produced, each with Grinnall badging. Cancelled variants TR7 Sprint A variant of the TR7 powered by the Dolomite Sprint engine (dubbed the "TR7 Sprint") was developed, but never put into full production; though British Leyland had the 16-valve engined TR7 homologated for use in competition. These cars