I recently purchased a 1949 Super in great shape and want to use it as a serious driver. It has a standard trans and I prefer an automatic. The engine should be rebuilt at some point. I need air conditioning since I am in Phoenix and would like power steering. My Dad had a 1949 Super w/Dynaflow. Although I was just a kid I recall the transmission was not impressive. I drove a 1952 Roadmaster with Dynaflow a couple of weeks ago and I was disappointed. My Dad also had a 1956 Super and I recall that its transmission was improved. I seem to recall a passing gear. Was there a meaningful improvement in the Dynaflow by 1955 & 1956? Looking at other threads I see that the 55/56 also had a torque tube suspension. I am wondering if installing a 1955/56 nailhead w/ Dynaflow in my 1949 Super is rather straight forward. Would the transmission easily adapt to the torque tube? I am also considering mating a modern auto trans to the Str 8 but prefer not to have to replace the rear end with an open shaft system. I like the Str 8 but also like the nailhead. I am concerned about significally modifying the car for I would like to keep it as stock as possible. But at the same time I want to making the aforementioned improvements. I may be rationalizing but I think installing a nailhead is less regretful than installing a modern rear end.