I am going to take the chance of being disagreed with and suggest your engine is suffering fuel starvation.
I do not like the OEM mechanical fuel pumps and I have changed them out for electric. I like to have a residual pressure/check valve system with a fuel return line to the fuel tank.
This system allows an oversupply of fuel to return to the tank. This keeps the fuel in partial circulation and the fuel does not slow in the fuel line and get hot. The heating of modern fuel happens at a lower temperature than the gasoline of way-back-then. When the gasoline gets hot, it can cause vapor-lock.
The electric fuel pump should be mounted close to the fuel tank. This will make the pick-up tube length shorter. Fuel is better pushed, after the electric pump. If there is a little pressure in the fuel line after the electric pump, this can help reduce vapor-lock.
https://www.walmart.ca/en/ip/HTRACING-A ... ABJ4LU3BXG IHC ran the fuel line around and close to the engine block. This is a bad design that easily heats the fuel to a vapor.
I will try and post a picture of the residual pressure/check valve with boost reference, I installed on my supercharged Ford.