GTO 3/2-BBL - Vacuum Actuated

[60sStuff]

Originally Posted by olredalert

----I'm curious weather big body Pontiacs followed the same path with the vacuum linkage on automatic cars? I remember a member here and friend, Chris P, had a gorgeous resto done on a 64 GTO convert with AC (triple black) and sourced all the vacuum stuff of the internet......Bill S

Hi Bill,

Yes, the Big cars used pretty much the same Vacuum linkage/components as the A body.

Although the Bigs did not use a throttle cable.
Instead they used link arms and couplings.

Thanks, Chris

[60sStuff]

Right Side.

Where would we be without Vacuum.

Brass fittings, steel pipe, crush clamps are what comes off the front carb throttle plate and provides Vacuum for the Power Brake booster, Automatic transmission module and the Vacuum reserve tank.

After this busy intersection comes a check valve leading down to a cast T fitting clamped in place.
One long hose goes to the Vacuum reserve tank mounted up front of the fender skirt.

The other, shorter hose goes to the thermostatic Vacuum control assy.
The purpose of this unit was to disable secondary throttle activation until the engine reached operating temperature (165 degrees).

[60sStuff]

Right side secondary arm operation.

End carbs were activated by a Vacuum Control diaphragm.

This “Control” mounted to the two RH rear carb studs and provided the pulling power to open the front and rear Rochester’s.

The two end carbs each had a small throttle return spring that clipped into the base plates to assist with deceleration.

The “Automatic” return springs #7013783 were twice the size of a “Manual Shift” spring #7029689 which (helped) on this Suicide Linkage.

I’ve seen many Original Vacuum Tri-Powers converted over to the Mechanical version and these springs were never changed out, because most are unaware.