Be sure to check the volume of fuel the stock Fuel pump is supplying. The PSI rating is important but volume is more important. If it cant keep up with the comsumption, you have no hope of carbs working to their potential. Weber DCOE's like 2.5 - 3PSI. Dellorto's like the same.
This is more critical when sustained high revs. A street car not so much. Also with mechanical type fuel pump that run off the camshaft, as the rotational speed of the camshaft increases the mechanical arm in the fuel pump can start to float and bounce on the lube, similar to valve bounce in the valve train and can start ti not pump fuel as well.
I run an electric pump which helps with consistent even delivery of fuel independent of engine rpm.

When I made the switch to running e85 ethanol fuel this becomes more apparent dew to the increase of fuel required for a correct A/F ratio. ~35% to 45% more fuel is used. Thin walled emulsion tunes and ~170 main jet size to feed a 1527cc A15.

Electric pumps can be had from the early 720 utes, I think some patrols had them also. facet make quite a few and so does nismo.

electric fuel pumps.