If you have a complete '39-40 Columbia it should fit under your '35-36 Ford with no trouble, that is if your car has been converted to hydraulic brakes.
If you are trying to piece a unit together you will need a complete '39-40 axle assembly, including the Columbia side, you can use the '35-36 torque tube and center section with '37-40 radius bars. The '37-40 bars are long in lieu of short like the later models. A 3/4" spacer between the bars and the torque tube mounting lug will correct the slight misalignment for the attaching bolt.
If you want to keep your stock wheels you can use the '40 drums for the '35 wires and '37-39 drums for your '36 wheels.. You will need an adapter on the '40 drums to properly mount the wire wheels.
The later model '42-48 Columbia shift controls work better than the early stuff and they can be concealed out of the way..
See the attached pix of how I mounted the solenoid assembly on the inner fender with the speedo shift mounted to the inside of the firewall on my '36 Ford.
Vacuum is no problem... I am running a 59AB engine, bored .60 over, Weber F1 cam, an Offy Super manifold with 2-- 97's.