I used a small can to free up a seized Chevy 292 six cylinder engine in a 1973 Chevy Stepvan, after being told by a number of mechanics that the engine would never run again without a complete rebuild. I drove the truck over 5,000 miles without anything other than an oil change and a news set of plugs.
It was a seven ounce spray can. I put approximately equal amounts in each cylinder and let it sit for half an hour. I poured a little gas in the carburetor and it fired right up after sitting over four years. It really freaked out a friend of mine that spent every spare penny and hour at the local race track testing his engines. :)