Weeds,
The tank you installed should have had some vent fittings up on the top of it that can be used?
Some questions for ya:
* How big is the filler nozzle and does it have any elbows or bends in it?
* Got any photos of the installation you could share with us?
If the filler neck is big enough and a straight shot down into the tank you could try sticking a long piece of half inch i.d., gas quality, rubber hose in the neck, running down into the top of the tank and then try filling the tank. That hose will vent out the air as the tank is filling. but that will only work if the filler neck is large enough not to restrict gas flow.
Similar to how they
vented the blazer style tanks.. except the tube was outside the neck....
