Find the TFI module on the distributor. Run your hand down the TFI wiring. You will find a small dangling pair of wires with a rectangular plastic connection. That's the SPOUT plug. Pull pn the plug while holding the wires. The plug will come out and the idle speed should drop a little. The SPOUT can be removed or re-installed with the engine off or on, it doesn't matter.
While you are working with the SPOUT plug, buy or borrow a timing light. Locate the 10 degree and 14 degree BTC marks on the harmonic balancer and mark them with a silver Sharpie (thanks to HISSIN50 for this tip) marker or white paint using a fine paint brush. Automotive touch up paint comes in a small jar with a brush and is excellent for this job.
Warning: there are only two places the spout should be when you time the engine. The first place is in your pocket while you are setting the timing and the second is back in the harness when you finish. The little bugger is too easy to lose and too hard to find a replacement.
Connect timing light up to battery & #1 spark plug.
Start engine, loosen distributor hold down with a 1/2" universal socket. Shine the timing light on the marks and turn the distributor until the mark lines up with the edge of the timing pointer. Tighten down the distributor hold down bolt, Replace the SPOUT connector and you are done.
Use a vacuum gauge ($17-$25 at most auto parts stores) to determine if a leak is present. You should see 16"-19" of vacuum at 650-725 RPM. At 1000 -1200 RPM you should see 18”-21” of vacuum.
Use one of the spare vacuum ports on the vacuum distribution tree that is mounted on the firewall near the windshield wiper motor.
Use a squirt can of motor oil to squirt around the mating surfaces of the manifold & TB. The oil will be sucked into the leaking area and the engine will change speed. Avoid using flammable substitutes for the oil such as propane or throttle body cleaner. Fire is an excellent hair removal agent and no eyebrows is not cool...
Check out the first picture here. That is what the actual connector looks like.
If you find your TFI module wiring harness and trace it backwards, you will see a pigtail sprout off. Go to the end of the pigtail and there's the connector. It might have tape covering it.
A vac gauge is useful for diagnostics if there's a massive leak or an issue with engine sealing. It's always nice to know what exact vac reading your engine has when running well so you have a point of comparison.
Good luck.
EDIT: JRichker and I overlapped. Not trying to be redundant.