We need to make some "separation" in this thread, there are two issues, and you may or may not be interested in both
That can for sale is overpriced if you need it and you may not. It is NOT for venting the fuel tank, it is for the fuel return system used on some cars. Only the hemi/ 440 HP cars in certain models used fuel/ vapor return
So...........
YOUR TANK MUST be vented
NO MOPAR ever came with a "vented" cap. The "vented" caps on some 70 and later cars were NOT really "vented" they were actually for pressure relief. The "real vent" is :
69/ earlier, the tube coming out of the fuel filler neck
Some 70 (CA cars) and all later cars with charcoal system the vent is the small line going up front which tied into this system. This is known officially as "evaporative emissions control"
IF YOU REMOVE the charcoal system, you MUST leave that 1/4 vent line OPEN and HIGH up front
VAPOR RETURN as earlier, is a SEPARATE issue from the VENT
Vapor return is designed to continuously pump a small amount of fuel round and round from the tank to the pump, through a orifice in the vapor return can, and back to the tank
YOU CAN NOT USE that existing 1/4" line for vapor return unless you provide a SEPARATE tank vent
FURTHERMORE the ebay can is OVERPRICED. You can buy Wix filters 33040, 33041, for 5/16 or 3/8, respectively, and accomplish "the same thing" for fuel return
Wix filter:
The small line at top, and it must be oriented at top as shown or vertically, is the1/4 return orifice
View attachment 1715050101
You need to get yourself a proper year service manual for your car and read through the fuel and emissions sections to understand these systems. GET THE CORRECT year!! These systems changed almost every year
Some of the manuals are available free, at MyMopar.com. Some of them there are due to the efforts of some of the guys on this board.