The 'split' for the two vacuum lines is the the brass fitting that screws into the back of the intake manifold. (photo #1 below)
The larger line goes directly to the power brake booster, only.
The smaller line goes directly to the top of a dual diaphragm fuel pump and the vacuum booster built into it. (photos #2 & 3)
In photo 4 you'll see a small part of the old mess left me by a previous owner...
The vacuum lines to/from the fuel pump almost look correct but are connected on the fuel pump backwards, and the rubber line from the fuel pump back into the firewall 'should' be metal until it passes the carb. This vacuum circuit powers the windshield wipers and Tee's under the dashboard to some control valves for the heater. (but I believe the hole in the firewall it passes thru in this photo isn't the 'correct' one)
In the last fuzzy photo (a neighbors '57 getting a water pump) you can notice the two smaller metal vacuum lines on the fuel pump are separate from, but run roughly parallel to, the larger vacuum line to the brake booster.
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