The high-speed Thruxton circuit in Hampshire is the venue for the sixth and seventh races in the 2008 Heritage Grand Touring Car Challenge during the British F3/GT meeting on 28/29 June.Thruxton, which is the only UK circuit with a layout that has not changed since it was opened in 1968, represents a unique challenge for drivers, with a series of high-speed corners split by two slower-speed complexes. With virtually no chance to test ahead of the race weekend, it will be a real test of car and driver. The weekend's pair of races marks a rare trip to Thruxton for the Heritage GT pack and the sight of these cars rushing up Woodham Hill to the chicane will be a great spectacle.The Heritage GT series of races for period machinery is a popular part of the British motor racing scene, with cars ranging from Mini Coopers to Ford Mustangs and from Jaguar E Types to Chevrolet Camaros and Aston Martin V8s. The very potent Morgan Plus 8 of father and son team Grahame and Oliver Bryant stands out as a major contender for victory. They took a great victory at Brands during the recent A1GP support races and can certainly win again, given that Oliver has pretty recent knowledge of the track from his contemporary GT racing.Thundering American V8s are always a popular element of the HGT entry and at least six of them will be on the Thruxton grid. Father and son team Arthur and Boysie Thurtle will be a major contender, along with the similar Chevrolet Camaros of Alec Hammond/Graham Hathaway and Rick Lloyd.The Ford Mustang of father and daughter Robin and Zoe North is also very rapid, while the Jaguar E Type of Mike Luck and Jonathan Edwards cannot be discounted in the chase for the podium. Meanwhile, the Aston Martin V8s of Chris Scragg, George Miller/Les Goble and Bob Searles/Tony Jardine will also be chasing a place on the podium.In class C for the less modified V8s, the hard-charging MGB GTV8 of Roy and Spencer McCarthy – another father and son combo - will be the benchmark and they are likely to be up among the very fastest cars in the race. A stunning line-up of six-cylinder Aston Martins will contest their own class, with the leading car likely to be the DB4 of Conor O'Brien and Charlie Kemp.Finally, two classes for the less powerful cars will produce races within the race, with the Ford Escort of Tim Glover/Rikki Cann set to be top of class B, while Kate Bennington fields her Ford Cortina Mk2 in class A.