So I just went to install an OSAC NOX Valve and as I'm reconnecting the "to carb" vacuum line I noticed that it wasn't connected to the carb and significantly shortened. Not to mention, there was a white flaky mess all over the manifold.
After some minor sleuthing, all I can figure is that at some point, the coil wire began arcing on another wire or the carburetor and the vacuum line got in the way. I came to this conclusion after discovering some singe marks on the coil wire.
I am running MSD cap and rotor, with MSD 8mm wires. Also using E3 Premium spark plugs. But ignition system is all stock. BWD Epoxy filled coil, brand new spectrum distributor. I noticed yesterday she was sluggish starting up, but then ran fine after warming up. A sluggish startup has been indicative of a vacuum leak, I guess this was it. I was lucky I even noticed the burnt off vacuum line, just because I happened to be changing the OSAC valve.
I fixed the broken vacuum line and electric taped the coil wire on the bad section. Anyone ever encounter something like this?