I will have to check my Hurst book , but I believe Hurst had a contract with Demmer Tool & Die Company in Lansing, Michigan to do projects for the big 3. In 68 they did the Hurst olds and also extened some Dodges for taxi cabs. Hurst did the 68 Hemi Dart and Baracuda, some of the 1970 Yenko Dueces, a bunch of AMCs, Grand Prixs, Chrysler 300s, and others. I believe they had another shop in Detroit in addition to the Lansing facility and their PA facility.