I keep trying to tell you guys, the filler problem has nothing to do with the vent, whether the vent is clogged, working or even present. The problem is returning air back up the filler as the tank fills. Part of the problem might be modern small nozzles with the pressure turned up way too high.
Having said that, unless you construct a separate HUGE vent, especially for the filler, say 5/8 (no 10) or larger, the filler problem is right in the neck. On my 67, no problem so long as I'm a bit careful "where I fill up." There are at least three stations nearby are normally no problem, and a some others I don't know, and three or four I no longer go to. I've complained to all of them that give trouble, I might as well go around and talk to the rear of the building.
