Idle for a while but cuts off/ revs great but cust off also

I have SU carbs on my 72 240z with a an L28 swap. I tried looking all over the forums for the past few days without much luck.

Here's my issue: Once I start the car it will idle fine for a good few mins. It will even rev as high as I want it to, but all of a sudden it would just shut off.

After a few starts I was able to isolate that this is a fuel issue. I sprayed carb fluid into the carburetors and the car would stay running. Once the fluid runs out it would die. As soon as it dies I can restart the car back up without a problem.

I also checked my fuel pump, it seems to be pumping kinda weak. (have a holly eletrical pump) I disconnected the fuel lines to the carbs and it is bearly dripping. I assumed I had a fuel pump issue. What would be a good flow rate and pressure fuel pump to get?

I tried a MR. Gasket 12s 4-7psi with 40gph and that flows a little better than what i have now. But I still have the same issue. The flow seems to be very weak, I checked the lines and it isnt clogged.

What is the correct flow and pressure? Any reccomendations on what fuel pump to get? Could this be a carb issue?

Any input would be appriacted.

Thanks!