The 1964 GTO didn’t just appear out of nowhere. John DeLorean’s perpetual quest for performance and innovative engineering solutions resulted in the very non-Detroit 1961 Tempest, with its hi-output four cylinder engines and flexible shaft drive to its Corvair-sourced rear transaxle and IRS. But a hot four was not enough, by 1963, and so the other bank of four cylinders was restored and the “326 cu. in” (336, actually) making a healthy 260 hp created the antecedent for the GTO.
Yes, the one proudly sporting the 326 badges.