Glad this thread came up since I am getting ready to go EFI with my 71 . I have a hybrid fuel tank also(CJ-5) , and I have been using the stock vent box, but I want to just get rid of it. Fuel Tank inc just uses 2 vents on their universal tanks. One for the filler neck and one other to vent tank to atmosphere. My problem is tank is right up against floor and the vent needs to stay vertical and there isn't much room to go anywhere. I could use the original vent line and run the vent up front and grab a canister off of some other car.
So doing all this emissions cause me to get check engine lights now?