Always wanted one of these https://www.ebay.com/p/1969-Holley-4604-s-Carburetor-3-Barrel-Carb-1050-CFM/1917819626
No . The Holley #4781 was the recommended Stage 2 carb and would be correct for 70 and up . Not to say that carb will not work with that set up
Some of the old B4B's had a notch in the divider so the single-blade secondary could open on the three barrel Holleys.
Yes,I recently bought an original Stage II intake from a board member,someone told me back in the 80’s when we were kids that the notch was to balance out the fuel mix or something but I can see what you are saying now. I might have to get one of those Holley carbs also just for display because I love that Quadrajet moan too much to swap plus factory air cleaner I guess won’t fit on Holley?