I would recommend everyone update with a roll over valve on the tank or in line in the hose, but this means the hose probably cannot be under vacuum as it will cause the ball to shut in the valve and block the relief air supply.
Are you tee'd into a true vacuum or the air filter? Personally I would not connect the hose to vacuum, you are sucking fuel out one end and the air out the other, something's gotta give either the tank collapses (and it has happened) or fuel starvation.
Julian
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