Runs then dies

What kind of clamps are on your new jumper at the back?
If gear clamps, it has happened to me that one clamp on each side, still sucked air there. So I put two on each side with the screwheads clocked 180*. That solved my problem. For me, the tell-tale was the filter kept filling up with air.

On another job, the tank was vented forward to the charcoal canister. That line was only very small, and it had rusted nearly fully closed under the passenger seat, the lowest place in the line. The cap was non-vented. So the car ran until pump could no longer pull fuel from the tank. When the car stalled, if you waited a few minutes, the vacuum in the tank would slowly pull air from the canister and equalize to atmospheric. And then the pump would pull again ........... for awhile.
I cut a couple of feet of the vent-line out and put a temporary jumper across, which solved the problem. Then I made a permanent repair.

On another job, the fuel seemed to be boiling in the pump or in the line from the pump to the carb. So I installed one of those in-line filters with the sideways third nipple, and plumbed that to the vent line back to the tank, then installed a vented cap; problem solved.

On another job, the return-spring on the arm inside the pump was too weak to keep the arm on the eccentric. So she pumped ok at low rpm, but as the Rs climbed, the pump quit pumping. That was a toughie, cuz it tested good at cranking and idle. It looked the same as a plugged vent. With the fuel-bowl empty the fuel in the line from the carb back to the pump would boil and the filter presented as empty.
Good luck