Personally, I agree 100% on the water in the induction system while the engine is running.
In the late seventies, gas was getting worse and there were no readily-available chemicals like today to do an upper intake decarbonization, except for GM "top cylinder cleaner".
I installed Edelbrock's "Vara-Jection" water injection system on my stock 429 CJ and it worked awesome. It allowed me to keep full advance and use the crap gas available then with no pinging or other issues. That system required constant refills of water (and a tiny bit of alcahol) and near-constant fiddling around with the keep working properly, but it served me well for many years.
Try this:
( as always...user beware. Any procedure I offer is under the assumption that the user has fair mechanical knowledge and skills. Don't do it if you are unsure)
1) get about 8-16 oz of whatever intake cleaner you want to use.( Seafoam is popular, as is ATF with old-school guys...I think ain old water is best)
2) get about 3-foot length of tinyest vacuum hose you can find.
3) put end of this hose in bottle of cleaner, to the bottom.
4) remove PCV valve from the hose feeding in carb base.
5) place other end of small hose from cleaner bottle loosely into end of open end of PCV hose. You DO NOT want a tight seal between these two hoses. Air leaking into the system as the engine is running is necessary for the procedurd to work.
6) start your engine. If it stalls out within a few seconds you have too much fluid flowing into the system...increase the size of the "air leak" until it will idle. Its tricky to get this part right, but you will get it eventually.
7) once it is idling, increase RPM to about 1200-1500 slowly using idle screw.
8) let all of the cleaner be drawn into the engine.
9) a tiny bit of constant white vapor from the exhaust is typical. Large billowing clouds of smoke show indicate that you are putting the cleaner in far too fast. Water produces a little vapor, Seafoam and especially ATF produce much more smoke.
If you get regular, rythmic "puffs" of smoke then you may have some worn rings or a valve guide issue.
10) when cleaner is done, let engine continue to run about 3 minutes to help excise any remaining cleaner in engine.
11) adjust idle back to normal
12) reinstall PCV as normal and you are done.
The air leak helps to atomize the water, allowing a larger volume of water to be administered, cleaning better.
Be advised, introducing ANY liquid into your engine in too great a volume can and will lead to "hydraulic lock". Fluids cannot be compressed and this can lead to catastrophic failure and damage to an engine, so...
Don't attempt it if you are unsure of your mechanical abilities.
