A Wonder Down Under

Our drag strip finally re‑opened last weekend here in Alice Springs. My ’71 Valiant Charger 360 keeps running out of fuel before the end and watch Dorfs and Holdens (GM) go past me as I coast over the line.
It’s not the fuel filter (replaced). I suspect my stock mech fuel pump can’t keep up. I’ve got a 360, balanced, .030˝+ bore, 10.5:1 compression, solid lifters, roller rockers, ported/polished heads with 150 lb. springs, 2.02˝ intake and 1.6˝ exhaust valves, split phase cam from hell, H.E.I. distributor and a six-pack carb set up with your excellent kick back line idea, and kept at 4.5 psi by silver soldering the return line and drilling out until 4.5 psi. Stock fuel lines. It goes through a T56 trans and 4.11 rear.
In desperation, I blocked the kick back line but still ran out of fuel.
I thought going to electric fuel pump, but besides all the $ is the noise, the aeration and heating of fuel. Current thinking and advice is a Holley 110 GPH mech pump, though I worry about the 6.5 to 8 psi so I’m guessing to add a regulator.
I’m going through a divorce, so $ is a big issue, and don’t want to do anything twice, which is why I’m writing you.

I suspect the pickup line in the tank, and the line from there to the inlet of the pump, are too small. Gotta be 3/8˝ minimum. Could also be a kinked line, blocked carb bowl vent, etc.
Also be sure the tank is properly vented.
If you don’t wanna do anything twice, simply don’t remarry!