I was at Jim Hales shop back when I first started my 68 fatback restomod. I mentioned to him that I thot someone had hacked in my 4 speed hump. He told me that all the barracudas (I don`t remember about the darts) that got 4 speeds were cut out very sloppy w/ a torch, and the 4 speed humps were tack welded-pop riveted back in, and covered w/ undercoating, and of course carpet up top. He said they weren`t designed for a 4 speed to start with, and that`s the way the factory did it ! I tend to believe him on that , he`s probably built -bought-raced and sold 60-70 of them over the yrs. He has had more than one original factory s/s cars too, also built a bunch over the yrs.