Aaron,
VC 310 is the geometry/angle of the bracket-angle for the units on the two 1954 235 Hydra-Matic engines that I have 9and on my other 54 trucks). This same unit was used on all 6-cylinder engines from 39-51 and on all 1952 through 1955-1st series trucks.
The angle of the other unit is, I think, more like the angle used on automobiles 235s from 52 and upwards (and maybe on 55 and later trucks?).
Part # 2.140 this is the vacuum control unit, not the bracket.
Those images are very interesting - I never knew that there were different specs on the vacuum control units. Does the catalog where you found the images indicate car or truck engines?
Here are photos of the two different style units. All my 54 truck units are like the unit on the right.
