https://www.jalopyjournal.com/forum/threads/bendix-brake-conversion.387348/
Check this out there is a heap of info on the Hamb on how to convert early Ford brakes to bendix operation
The internal winding of the coil is loose and when you brake the winding swings foward
and shorts out on the body of the coil cutting spark to the engine. When you have finished playing around with the carb, change the coil and see what happens.
I used a master cylinder from an early 70's Ford Torino. Probably the same as the F100 mentioned above. Drum/ drum worked perfectly. Had residual pressure valved fitted in the master cylinder.