[alex21278]

Hi all,
Im new in this, only 21 years old and working on a 1965 Pontiac Star Chief, 389 V8, 2-bb with AC and I’m trying to confirm the factory vacuum routing on A/C cars. I read 1965 Pontiac shop manuals and read forums but still wanna get confirmation.


My understanding:

Non A/C cars: rear vacuum tree block on carburetor with 3 connectors
Right → brake booster
Middle → TH400 transmission modulator
Left → distributor vacuum advance

A/C (my car):
Right → brake booster
Middle → TH400 transmission modulator
Left → through firewall to HVAC (with check valve). Instead distributor takes ported vacuum from the front of the carb and is connected with a steal pipe.

Can A/C owners of ’65 big Pontiacs (Star Chief/Bonneville/Catalina/GP) confirm this and share any photos/diagrams? If you’ve swapped to 4-bbl, did you keep the same logic (tree→HVAC, carb front→distributor)?

Pics of my setup attached.

[Rachelsdad]

Welcome, Alex!

It's been a day since I've had eyeballs on an AC car from that era with a 2bbl, particularly a '65.

That said, there is a fellow in Switzerland (no kidding) with what looks like pretty much a survivor car (another Star Chief, like yours) who may be able to help:

https://foreverpontiac.com/forums/to...65-star-chief/

He may be able to shed some light on your inquiry.

[TXSTARFIRE]

I think an A/C car would still use manifold vacuum for the advance just like the non-A/C car. I dont think ported vacuum for advance was used until about 1968.

[6262]

My discussion with another '65 owner yielded the attached result.

Quelle 1 = source, ported
Quelle 2 = source, manifold
Getriebe = Transmission
Bremskraftverstärker = brake booster
Gaszugdiaphragma = throttle pod
Heizung = heater
Verteiler = distributor

I am not sure if this is correct. This was my assumption from asking and studying the manuals!

http://www.directupload.eu/file/d/9066/he4u8ghu_jpg.htm

I have no idea how to insert a picture here...? How do you do it?

[Rachelsdad]

I have no idea how to insert a picture here...? How do you do it?

Use the "Go Advanced" button, and below the advanced composition input box (where you type your reply), use the "Manage Attachments" button. You should be able to figure out how to attach images from there.

HTH