Dies when Secondaries Open (Fuel Shortage?)

[RhapidFyre]

I'm back again! I got some videos below showcasing what's happening. We have replaced ALL of the fuel supply except the gas tank itself. New fuel sender, new hardline, new mechanical pump, new carburetor.

The problem is that I got an Edelbrock 750cfm for a 350 small block, but what I'm reading online doesn't indicate our problem is being caused by being over carb'd.

Originally, before we replaced the hard fuel line, we could rev the truck up and take it out on the street. It would have insane take off, burning the tires, but as soon as it ran up through the first gear, we would lose it and have to limp it back to the driveway, because any tap of the gas pedal resulted in the vehicle dying.

Now, it's doing it just being revved up high. My father-in-law is a mechanic, helping me with this truck, and he's even out of ideas at this point. My uncle, Jim, recommended getting smaller jets for the Edelbrock before I dump money on a 600 cfm. We are doing that next.

Here are the videos showcasing what our problem is.

Overview: https://www.youtube.com/watch?v=6ntk1YdL8W0
Up close: https://www.youtube.com/watch?v=YwuNXMgy8eU

[EDIT] -
HEI Distributor
New Spark Plugs, 0.35 gap
Tried going straight into a fuel can, didn't change anything.