DDK - Die Deutschen Klassiker

Appreciate help with the following:-
I notice whilst driving that I had to push the brake pedal very hard to stop, no servo.
I have no Vacuum at master cylinder which is 78 SC shell & 73 2.7MFI engine, I followed the hose from master cylinder to engine Bay and it was plugged with a bolt and hose clip. How is this supposted to work ? Do I need to extend the hose and connect it onto the air filter manifold vacuum conection Or where do I connect to ? Its currently terminated at the fuel filter. Or what is this modification and how does it work. any ideas ?

It will need to be connected to one of the inlet manifolds to give a vacuum, since none of the cars with that engine had servos I presume you will have to modify it in some way.

You could fit an electric vac pump as used on many cars (diesels often). It might need a pressure switch though, to switch it on & off.