The (“vacuum”?) check valve located on the firewall connects to the carburetor via a hose and to a cylinder located below the passenger side; from this cylinder another hose comes out and is not connected to anything. Could someone please help me with figuring out if I need to keep this check valve or not once I assemble the truck back together?

 

As I understand it the check valve helps maintain the health of the vacuum system. You don't want fuel fumes to start eating away at your seals and diaphragms! If you plan on using any vacuum accessories, install the check valve.

See: https://www.ford-trucks.com/forums/1...r-mystery.html

 

Is this reservoir for brakes on bigger trucks? if so yes, it maintains vacuum reserve to the brakes if your engine should die for some reason and you will need to stop. Other than that I don't know what the reservoir is used for. If its not then just plug it at the carb fitting. Is it a reserve for your vacuum wipers? Sorry I am not much help but there are bigger truck fans on here I am sure can help.