Where you measure pressure matters. Higher up the motor lower the pressure. You would expect a pressure drop across the vapor separators.

What is more critical is good volumetric flow for the motor needs. Pressure is the means to get that flow.

Also, all 440 do not have vapor separators, and the spec applies to single 4 barrel too.

I have rebuilt several Carter pumps used on Hemi motors with no issues. I know the builder also uses the aftermarket ones when numbers don't matter.

Never had a problem. I just think the statement that the needle can't handle more than 4-5psi not accurate.

I would be looking at quality of the needle and float setting/alignment if a stock pump flooded a carb.