Who's idea for the 68' Hemi Dart

H-Cop, I believe they were Porsche Racing Seats for the Test Mule.

You're 100% correct! Pat McGroder here in Phx had the "mule car" in his collection for awhile & I got to crawl around it. His crew showed me all the R&D paperwork & photos that went into that car & it was amazing! It wasn't just a couple of hotrodders trying to stuff a big engine into a small car--they took EVERYTHING into consideration. No wonder it was so successful!