[Rockdriller]

Quote
"3. What is that canister mounted on the driver's side fender near the master cylinder? It has a vacuum line connected to the intake manifold and another line going to the oil filter mounting assembly. ?????"

Randy

Well, as far as I can guess without looking at it...
That is a "Vac. Reservoir". Just like an air brake system uses air tanks to store pressurized air, the larger trucks with juice brakes and vacuum assist need a bit more vacuum at times than is readily available from the engine.
Think about what happens to your vacuum on a long down-grade in a lower gear...
It's nice to have that stored energy when you really need it.
There should be a one way check valve in-line from the manifold.