I forgot to attach a picture of a vacuum tree.
There are a couple different versions of them, welded steel and cast aluminum. The aluminum is not as strong and can be somewhat easy to break when removing.
Of each type, there is different versions as to how many ports it has. A more highly optioned car will have more vacuum ports.
Pictures were swiped from internet.
This picture is from my ’87 Fifth Ave - so it is close but not exactly the same as yours.
White circle is vacuum tree. Black arrow is the power brake hose. The red arrow is the plastic vacuum supply hose - which might be a different color on my '86.
The power brake hose attaches to base of the Holley 2260/6280 (which you have on your car). The power brake booster attaches to vacuum tree on the Carter BBD.
Your car should have the Carter BBD on it – so I suspect your engine might not be original to the car, possibly.
If that is correct, then the/your vacuum chart/diagram will not be exactly correct, either (mostly, but not exactly.
BudW