It would be overly coincidental that your fuel pump would fail exactly when you were removing the gas tank. Two possibilities:
1) In my experience, it takes a surprisingly long time to suck fuel from the tank to the engine. You might simply not run it long enough to fill the lines.
2) SBCs are a puller pump. In all your finagling, you may have created a slight leak in one of the fuel line junctions which is now sucking air. Since air pulls easier than liquid, the pump will just continue to inhale air at the leak and never suck up the gas.
Recheck and retighten all junctions, then fill the carb with gas (through the bowl vents, not the venturies) and keep running it non-stop until it fills the lines.
