here is a link to a thread here with a cutaway of the filter and some chat on pressure variations with new filters and also how the lines connect. scroll down for the cutaway pics
if a stock engine the pressure differences that can happen wouldn't be a big deal. on a high horsepower engine the pressure differences would be a big deal as well as the restrictive fuel line size (3/8). big hp engines would likely need a larger fuel line size to supply enough fuel, especially on long fuel line runs and if hose is used instead of steel lines (there is friction loss inside a rubber hose compared to steel lines).
https://www.67-72chevytrucks.com/vbo...d.php?t=699891