I actually have one of those small smoke machines Wal-Mart sells during Halloween. I've been thinking of ways to make it practical to do smoke testing, otherwise I'm stuck with a vacuum gauge and testing various points with the engine running.
Speaking of vacuum leaks, all is not well in the valve cover. Before I change the air filter I inspected the PCV breather and again after a week on the road I've had oil burping out of the valve cover, up the breather hose, through the PCV breather filter and into the air cleaner, so there's no point changing the air filter yet.
I tested the PCV valve and found it was behaving as it should and found a decent vacuum going through it and into the valve cover and sharing the same vacuum with the charcoal canister. What I did not find however was a vacuum at the air cleaner breather. It must be pulling a LOT of air from somewhere to defeat a 20 inHG vacuum and there was not a lot of indication of serious blow-by. There's an oil leak from the valve cover gasket above the manifolds, so we might have to first start there.
Yes you can set the computer into various open and closed loop modes manually. The mechanics handbook specifies how to jumper the diagnostic connectors to fool it into various states. Speaking of carb rebuilding, there was a partial rebuild kit that came with the car so indeed, there has been people inside the carb body. I know there's at least one shop in town within a stone's throw of my workplace who does rebuilds.