Curious if anybody remembers doing this...
When I was little, before we had a pipeline milking system, before we had a generator, we could milk the cows using the H.
If we lost electricity, we'd pull the Farmall H up to the front of the barn. There was a spigot on the intake manifold. Simply by attaching a hose from there to the vacuum line that ran the milkers, we could run 2 Surge milking machines. The H would just run at idle. The pulsators ran off vacuum, no electric pulse needed, and the cows would get milked. (Took twice as long, 2 machines instead of 4)
These are the milking machines we used: