Vacuum Linkage
 

I would like to see and compare the Rare Vacuum Linkage on the 64-65-66 GTO's.

Most all the V L was removed from the 64's and the 65-66 Automatic cars in favor of the mechanical linkage.

Today it's a rare site to see one in the factory configuration and working.

Anyone with a "Correct" OEM system please respond to this NEW Tri-Power Tech section.

Below is a 66 unit in perfect working condition.

I have done a few of the Vacuum set-ups over the years and your unit looks very nice as it and with a bit of detailing could be a real show winner.

Tom V.

Not sure how much help this will be, but here are photos of the vacuum linkage parts we did not re-install on our 64. Not even sure what it all is or where it all goes, hasn't been on the car since about 1970.

Anyway, maybe these can provide some reference points to someone down the line. The thermal switch that goes into the front of the intake manifold got lost some years ago.

Thanks for the pictures Rich.

Tom V.

THANKS!
 

Tom, detailing I suppose would look nicer, but I like the old rust and patina of 50 years.
I'm a Survivor kind of a guy that likes old cars showing their age.

THX, Chris.

Agree, but the wood trophy guys judging the shows think otherwise usually.

Very complete and again thanks for the pictures.

Tom V.

tri power picks
 

hears the set up mike did for me on my 64

Here is some Pictures of my 66 TP,it is a Freemont build car, sold new at Doten Pontiac,Oakland CA. I im not certain how correct it is but i think most of the parts is there. I now for sure that the throtthle cable and spring is not mounted as it should,and i made a New bracket for the washer tank as it wouldnt fit right where it should,cause of the vacuum canister.But there is certanly other things to.
I have owned this car for 3 years now and this is the 4'th summer in the car. Car runs great ,and i wouldnt think of change the linkage to mechanical, and miss the moment when the Outer carbs suddenly kicks in. I drive it almost every weekend from mai to october and never have experienced that the carbs stuck open, but im not going at full throttle EVERY time:D.
There was missing some of the vacuum tubes when i got it and i didnt manage to find the parts i needed, so i made some of them looking on pics. (Thanks Chris).
It also has the 614 option,that i understand is a California only thing.

66 Vacuum Unit
 

It’s been over 3 years since this thread was initiated and I receive questions on occasion when someone is trying to reinstall / or just duplicate one of these rare units.

The 64,65,66 Tri-Power GTOs with factory Vacuum linkage were for the most part the same with no less than 12 components for operation.

One piece “steel lines” were used for the plumbing, along with brass fittings, tee fittings and short hoses.

The automatic cars used different style vacuum lines for the transmission.
I have seen a couple variations of this steel trans. line on 64/65, but 1966 transmission vacuum line was unique for this last year.

Below are close-up photos showing how the factory assembled this particular 66.

Chris.

Few more.

This car came with PS, PB, Automatic and was assembled at the Fremont factory with the #614 air cleaner option.

Chris

Vacuum reserve tank.

Heavy return springs.

Vacuum spring next to a mechanical spring.

Chris.

THANKS Chris. Third pic is great. I did not realize the rear alt support arm ran BETWEEN the ports on the TVS.

And the vac can looks the same as 64-65, same feet. Thank you!!!

"Bill"!

Hi Bill,

Yes, if you have “Power Steering” the car required 2 support straps.

I have 4 different Original 64s on file with Vacuum linkage and all of them do not have PS.
Consequently they have just the one long support strap for the Alternator.

I would love to see a 1965 Tri-Power Automatic GTO with factory installed Vacuum linkage, but I do not know of one.

Chris.

So- how quickly/slowly do the end carbs close with those HD return springs? Did Pontiac ever figure out a way for them to not be fighting the vacuum diaphagm when closing?

They close in a little less than one second, but that seems like a longer time when you're behind the wheel. This has scared many of us with Pontiac, Olds, and other factory vacuum linkage. I wonder why this is not an issue with Holley (3310) & other four barrel carbs that use vacuum to open the secondaries. Quadrajets close the secondary throttle plates mechanically, so there is no delay with that carb.

The vacuum switch on the center carb vents the diaphragm to atmosphere instantly when the accelerator pedal is released. But, the volume of air needed to release the diaphragm takes time to fill and release the diaphragm.