Since the topic has been moved to HiPo I decided to add more food for thought.
The 1957 235 engine has FRONT-side mounts (car and truck). The original 1950 216 engine mounted in the FRONT-center at the support below the timing gear cover. To use the side mounts you have to make or buy a bracket on each side going to the frame (weld-in or bolt-on). If you do the front center mount, you only have to drill new holes (investigate yourself). Whatever you decide to alter on the bell housing support/crossmember will most likely negatively affect the alignment of the front mounts.
At one time I owned a 1950 with a 1957 235 engine. The old style bell housing was used and the front support was drilled for center mount. It had a 3-speed Saginaw transmission (column shift) and rear axle that came from a 1968 Camaro. At the time this was the logical way to do it (old school). Less labor to put it together. Parts could easily be found in the wreck yard. This was once the combination to have that gave all the speed you needed for sensible driving (not negotiating 75 mph expressway traffic).
Today the popular manual transmission that best fits the nature of a 235 (reported by several Stovebolt members) is the T5 (with the preferred gear ratios). This has to be coordinated with the gear ratio of your rear axle. The 235 is designed as a high torque low RPM engine so the gearing of the T5 has it's benefits for highway driving.
The SM420 is an excellent heavy duty truck transmission with a granny 1st gear (7.05) for hauling on steep mountain dirt roads or working in farm field.
