Disconnected the T as instructed by Brian. Pumped up the mityvac and it goes down to 15 inches Hg and stays there. Then gradually bleeds down to zero over a looong time...more than 5 minutes.

But heres the realy clincher...the T on top of the VCV is connected to absolutely nothing....I cannot find any lines going to the T. Can anyone share a picture of a proper vac line setup for a 300TD (circa 1983) with this forum please?

Thanks!