[Tom Vaught]

It has been posted several times in other threads.

When the Service Package parts for the Mechanical Linkage 64 Tri-Powers were offered to the parts people, they needed a
"Mule Set-up" to verify the parts apparently worked.
My car was a "Brass Hat" car. That means a high level Executive drove it before it went into the public sales que.
At Ford, we called that "B-plan" vehicles. Vehicles owned by GM that were driven by Pontiac Exectutives would have a similar plan.

A person could "Tag" a vehicle for purchase (after the Executive drove it a year) and you got a great deal on the price.
So my Uncle, a Pontiac dealer for 67 years, knew the Brass Hat at Pontiac who was over National Pontiac Sales.
When he turned in the vehicle, my Uncle tagged it for me.
1964 Tri-Power 4 speed, Convertible with Metallic Brakes, Reverb, Wood Wheel, and several other options.
It also had the Mechanical Linkage Tri-Power on the engine.
So obviously the engine probably came down the line (in April) with the Vacuum set-up on it but the intake/Tri-power was removed (for the Brass Hat) and the Mechanical Linkage set-up installed. (Complete with Rochester Products Engineering Part Numbers on the parts.) They released the Service Parts for the Mechanical Linkage also in the April/May time frame to the parts distribution people.
I spoke with the Rochester Engineers years later when I worked for Holley carburetor and they verified that the set-up was a "Test Part for Evaluation by a Pontiac Executive". Pontiac Eventually released a Kit for other 64 GTO guys thru the parts system, as mentioned above. Dick B has that info (as he very accurately reproduced the 64 Service Parts) based on the info I provided from my Prototype Test set-up.

So I am saying the car was built in April and Rochester and the Executive knew the special Intake/Carbs were coming. I can't say where the swap was made or if there was a swap, after it came off the line vs just installing the parts on the Brass Hat's GTO at some point where they normally would install the Vacuum set-up.

I cannot answer your question on that deal as never worked in a plant like Keith Seymore did. But my deal is the original 1st set-up for the service parts.

Tom V.