V8 to /6 vacuum advance

Pull the distributor cap so you can see the arm coming out of the can. Suck on the vacuum hose and see if the arm moves. if it does the can is OK. Might just need some light oil (3in1 or Hoppes) on the advance mechanism. Might want to try adjusting the can if it's good and oiling things up doesn't fix it. Stick a 3/32" Allen wrench in the vacuum hose nipple and you can feel the adjuster screw. Clockwise for more advance, the other way for less. It's a process. Tweak and drive. Tweak and drive. Tweak and drive...