Thank you everyone for your advice!
I have scoured the internet and can not find the correct part.
I am tempted to solder in the additional return line to my NOS C-body sender. But I am afraid that the heat required would ruin the plastic insulators for the wire, not to mention ruin the coating.
I am looking in too sending the old unit out for restoration. But it is terribly rusty as it sat in bad gasoline for 11 years! I did get a new tank, pad, rubber hoses, clamps, etc.
Does anyone have an opinion about adding a fuel bulkhead connector from Earl's or the like???