[GregWeld]

The one I just finished I added a 1/2" vent from the top side of the tank near the fill tube and ran that up to near the top of the fill neck. That way any slosh went right back down and the fumes and pressure just went from the tank back to the tank if that makes any sense.

I think you absolutely need a vent. Or suffer the backsplash like an old chevy used to give you -- a nice douche of fuel...





Took this pic before I started welding up the sump.... NOTE my big red felt tip pen --- BECAUSE I WAS REAL TIRED OF THE FUEL DOUCHE!





This is the tank from my Nomad -- which began life as a carbureted car - so I decided that the EFI needed a sump etc....