Would This solution bleed off half of your available pressure tho? it seems that just maybe your 5-6psi mechanical pump wouldn't be able to put 5 psi to your carb anymore w/ a return line.
Is This a thing?
Looks like a Broken Remnant left on top that used-to scrub fit to the top...
Pull it out and look in there to see if there are witness marks from a scraper