On my 92 FlareSide it has twin tanks. Both tanks have 1 of the 2-port vent valves broken. Luckily it is the port that goes to a hose that's capped at the end.

When I order the replacement I need to know if the 1-port vent valves will work as opposed to the 2 port vent valve? The 1-port vent valve is 20 bucks on lmc and the 2-port is 120. I need quantity 2 of the 2-port vent valve unless the 1-port vent valve will work. Any thoughts to this?