Thermostat TVS

[44SAA]

Howdy-
Can anyone ID this port on the firewall and it’s function? The hose from it connects to the TVS. Installing new thermostat housing and wondering if I can delete the TVS.
Thank you

[MJN]

Your brake booster should have a constant source of vacuum, if it is not plumbed to a fitting on the back of the carburetor base plate then it should be connected to the intake manifold. There is a vacuum port behind the carburetor that can be used for vacuum for the brake booster. Looking at the vacuum schematics in the service manual there shouldn't be a connection to the brakes for this switch. The main vacuum source should be coming from the carburetor to the TVS.
If you remove the TVS and install a 90-degree fitting as shown your coolant will all be lost. The TVS uses the coolant temperature to control the vacuum to the different ports for EGR valve, and fuel evap system.- its a thermal vacuum switch to control parts of the emissions system. If the TVS is not used then remove it and plug the water neck with a pipe plug.

[44SAA]

Thanks- I just realized the hose from the TVS doesn’t attach to the brake, but behind it on the pass firewall. I added a picture of it on my initial post. Not sure what I was thinking on the 90 port- embarrassing

[truckin 79]

Yeah that is just for emissions purposes, so if you dont need to worry about emissions then just reroute vacuum hoses to bypass that TVS. All you need is vacuum to distributor, vacuum modulator to transmission and egr. There is one port on that TVS that has constant vacuum I forget which one.