Stabil is an additive that's supposed to keep gasoline from going bad. It used to work great, but doesn't seem to work as well with the crap gas we have now.. You'd put a pint or so in the tank and fill her up and run it a few miles.. I would do that, and then drain as much gas as you can out of the carb, and seal it in a plastic bag and keep it in a dry spot..
Another trick an engine builder told me is to rev the car up and pour Marvel Mystery Oil into the carb until it stalls out.. It'll smoke and maybe foul a plug after you re-start the car down the road, but it leaves a nice protective coating in the cylinder bores, so the rings don't rust and stick..
Kenny