The new 670 Avenger has 3 vacuum ports. There is one up front, next to the sight plug, and two on the bottom front below the fuel bowl. I assume that.......

The one next to the sight plug is for vac advance
The small one below the float bowl get run back down to the transmission
The third, larger, below the bowl is obviously PCV.

Do I have it right?

Secondly, there is no provision for the brake booster, again I assume I just go right into the intake manifold for that?

(I bought it refurbed, no instruction manual!)

 

Sounds like you got it right (at least that's how mine was.)

You always want to go off the manifold for power brakes, so you need a fitting to go from the port on the intake to the brake booster.

 

Now you have a manual: http://www.holley.com/data/Products/...99R10219-3.pdf
Read page 6

 

I disagree with where they say to tap for power brakes. I was always taught to go off manifold vacuum and not port vacuum.

 

That tap is in the base plate, manifold vacuum.

 

Yeah, looking again you are correct. However I was still taught tap directly from the manifold as gunk and carbon deposits can build up around the ports on the base plate, reducing the efficiency of the power brakes.