If you're talking about the vacuum advance for the 216/235 distributor, then yes it has the vacuum advance, which runs off a carburetor connection close to the idle adjustment screw.
Yes, it does have vacuum advance.
what is vaccume advance mechnism
Remove the distributor cap. Remove the hose to the vacuum advance. Remove the two screws holding the vacuum advance on. Install in reverse order.
Chevrolet didn't make a 464
The best way to repair a vacuum hose on your Chevrolet is to replace the vacuum hose. The vacuum hose is held in place with a retaining clamp on each end of the hose.
Going up the scale from "0" the 4th mark is 8 degrees. Be sure to check the mechanical and vacuum advance as well.
Ported vacuum - part time.
pull the hose off the vacuum advance and some of them have a set screw inside the hole.
YES! Any time you adjust the timing you should disconnect the vacuum advance.
800rpm manual transmission, o degrees advance 1200rpm automatic transmission 4 degrees advance
"VAcuum advance". Step on it, vacuum goes down and it advances timing for more performance/power. Idle of letting off, advance goes back to setting for economy.
You can find a 1986 Winnebago, with the Chevrolet 454 cubic engine, vacuum routing diagram at most Chevrolet dealerships. The vacuum routing diagram can also be found in most Chevrolet engine service manuals.