Pre early 60s cars had four point mounts -- usually two near the front of the engine and two on the bell housing. That's right, the transmission just hung off the back of the bell, even those old heavy Dual-Range Hydramatics! A lot of bells were cast iron back then too though. I know Rambler (AMC) used an aluminum bell with the cast iron Borg-Warner M-8 (Flashomatic) with cast iron case, don't know about the mid 50s D-R-H trans.
The main reason for four mounting points was so that there was nothing under the engine that couldn't be easily removed. Oil filters were optional until the early 60s on most engines, and many had no factory option at all until after WWII. Non-detergent oils were used that didn't keep trash suspended in the oil. The oil pan was supposed to come off and be cleaned once every year or two. Trash would settle in the bottom of the pan when the ND oil stopped circulating and cooled off. Detergents in oil keep particles suspended so the filter can catch them. Even partial flow systems worked well. The old Rambler 196 (OHV and L-head) used a partial flow system. I've rebuilt several -- none showed any more wear than full-flow filter system engines.
Hmmm.... that would have been a good question, but I've already typed up the answer -- not deleting now!!