> next month. I am also looking for a Vacuum Switch? (I have heard it
> called a
> million things. (Thermeo vacuum valve, etc) I attachets to the carb and
> the carbon canister. If you know where I can get on please inform me.
> What other things can I do to this engine to get all the performance out
> of it? Four Barrell Carb? Is it worth it? Anyone have a 400 or 455 GM
> engine for
> the year 1972?
The typical hose arrangement back then for the carbon canister is a a vapour
line from the gas tank, a small vacuum line going to ported vacuum, and a
line from the carbon canistor to the PCV, and from the PCV to the
carbourator base.  No switches along the way.  Just nice simple plumbing.
The thermo-vaccuum switch is the control valve thats found in the air
cleaner snorkel which directs air from the heat stove, or ambient air. Its
hose arrangement is simple as can be, thermo to temp sensor (in airfilter
housing) from temp sensor to manifold vacuum source.
The only other vaccuum operated system would be the vacuum advance for the
distributor, no switches, just run straight from a manifold vaccuum source. 
And if you have EGR, that just runs to a ported vacuum source (if, and it
probably is, a single diaphram type).
There are no vacuum delay switches, no one-way valves, just straight
plumbing. But, just in case I am wrong, verify the facts with a shop manual.
Check your local library, they typically have many service manuals on hand
for old domestics.
 | AmiQWK 2.7 - S/N 0261 |
... sit down, strap in, shut up, and...HANG ON!!
--- OLMS 2.60p.a1+ [EPMAP55A]
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