Keep in mind they changed the spline angle sometime in the mid seventies so earlier output shafts won’t work in later planetaries and visa versa. Your 74 came with a divorced 205 and a stubby 727, lockout hubs and drum brakes. The OP truck looks like a later model CAD setup. Your 74 didn’t have overdrive, and if you are going with a new hemi the small block case is the way to go since it will pretty much bolt on.
