Thanks for the advice. Simple, I suppose, but I was sort of scratching my head (not knowing that the tank and neck were two pieces). Fortunately, the filler neck was easy to get off and easy to figure out how to remove. Inside my filler neck was a funnel-shaped spring that was held in place by friction. It was a bout 8 inches long and obviously is an anti-siphoning device. I'm assuming that this wasn't stock.
Since it's not a daily driver, I yanked it out so that I'd have easier access to siphoning my tank, should I ever need to again.
The tricky part is getting all the gas out. Went from 3/4 to 1/4 tank pretty easily. Can't seem to get a pull on that last 1/4 tank. Will try jacking up the front end to create more of a pool.
The springs became popular during the Mid-East gas crisis of the mid-70's and, yeah, you might want to reinstall it to prevent loss of the current liquid gold too......
You can buy a small, hand drill powered pump, that works well for the last bit, because it actually pulls the liquid rather than depending on gravity to siphon. You should be able to move the suction hose around enough to get almost all of the gas out. Depending on how old and smelly it is, filling the tank with fresh gas will dilute a gallon or so of old enough to not matter.