filler neck modification

I finally got around to ordering one of these flappers. Installed today.

I broke 4 tabs off the top. Left the 3 centers intact. Tweaked the 3 top tabs and bottom tabs to make the piece smaller in diameter. Inserted the top half first then bottom so it sits at an angle. Used a mallet and screw driver to tap bottom teeth in to make piece sit perpendicular to the tube. It's installed about 2.5" deep

I tried the wooden dowel trick.. it was just a waste of $4 from home depot as I could not possibly see a way that work what so ever. Just way too tight a fit. In fact you cant even open the flap inside the tube until it sits up straight. So that tapered dowel trick would be impossible.

Now for results.
I can set the pump and forget it on the low setting (on the high it took about 10 seconds until it started backin up and spewing gas.)
It will shut itself off but will spew gas out the filler once the tank is full. So just shut it off before it gets to that point. I no longer need to hold the pump at a 45-90 angle the entire time.