This car was at the Peach State Chevelles show.
Real nice guy. I spend some time talking with him about the intake and car.
To fit under the stock hood, he needed to use a lo-rise OEM tri-power manifold. The motor in the car is a late 502 (if I recall correctly).
I checked on prices for the BG, basically $2K to $2400.
There's a real nice lo-rise on ebay for $1500 (may be negotiable) and you can buy new carbs for $1200 (also maybe negotiable. 10 sets in stock), AF and associated parts about $400-$500. Get the manifold restored ($200).
It fits..I know, I "seen" it!
If you ever change your mind, you will still get pretty darn close to that for all of the parts. They aren't making them any more (only the 67 version is done repo)
If you do the BG, you need a new hood $300-$400 plus paint)
http://www.carhoods.com/WhereTheWildRidesBegin.htm
If you ever go to sell the BG, you'll get 1/2 back...maybe 1/4...maybe.
My recommendations is that if you are going to do a tri-power, go stock.