Terry Sure. I'm game. The 413 Imperial engine was correct for the designers and planners of what an Imperial should be in their minds eye. In 1963 the model 91's, 92's and 93's all had the single exhaust...except the "rag-tops". The "rag-tops" could be had with the dual exhaust. Even so, they were all rated at 340 hp and 490 lb's of torque. For the tonage the Imperial needs the torque. Mean while over in the Chrysler's, Dodge's or Plymouth's one could get a 413 with 410 hp. Now they had true factory high compression engine. Got to go... Rodger & Gabby