Fuel line diameter and fuel pressure Options

[Scott S]

Hi All –
Will reducing the diameter of a fuel line cause an increase in fuel pressure?

I am installing my fuel distribution block tonight. The line from the fuel pump is 3/8” and goes to a 3/8 barbed fitting on the inlet. The outputs (two of them) are 1/4” (using a 1/4” to 5/16” barbed fitting on each output). The fuel line is 5/16 from the outlets on the distribution block to the PMO fuel rails on the carbs. Attached is a pic of the block itself.

The reason I am asking is that I will be installing a fuel pressure gauge and want to get as accurate of a reading as possible. There is a perfect place to install the gauge on the 3/8” line going into the distribution block. However, if the reduction in line size causes a pressure difference, I will obviously want to find a location on the output side on the lines going to the carbs.

Will installing the gauge on the inlet side work? Am I just being too anal?