It runs out of fuel because of insufficient fuel delivery. That carburetor number with a .135" N/S assembly should easily stay full on hard runs at your power level.
I'm not much of a fan of using an electric pump to feed a mechanical pump but I've seen some folks do it with decent success. That deal didn't work at all for my car way back when I was using a 455 only making 1hp/CID.
A lot depends on the pick-up location in the tank and if it gets uncovered or not on a hard run with traction.
The length, size, number of bends etc with the fuel line to the pump is also a player here. For sure it is easier to "push" fuel 14' or so than to pull it that far when you find good traction and the car is pulling really hard thru the lower gears.
You are also feeding 455cid, so fuel consumption is great at full power. In any and all cases the correct fix is to keep the carb full on hard runs. I'd start out with the Holley Red pump and see if things improve.
You can also try a larger fuel inlet seat, we have them clear up to .149" although I'd recommend no larger than .145" for that carburetor with the stock size float in it unless you have a regulator......Cliff
