Is "Stop Leak" Snake Oil?

My niece just picked up a 66 Mustang that sat around for about 10 years. We changed the rotten hoses, flushed out the radiator, got a new battery and it started right up after fiddling with the carb a bit. It purrs like a kitten and runs pretty well for a bone stock 289. But, it leaks oil all over the place. Rather than tearing into what seems to be a pretty nice original engine (116K miles), should we put in some of that Stop Leak stuff, or some other product that softens up all of the gaskets and seals again? I think they're just old and allowing oil to pass through. But of course, I don't want to clog anything up. What do you think about these products? Are they safe?

snake oil....

on a car like that, you most likely have cork gaskets (intake, valve covers, oil pan) which have detoriated and cracked. nothing short of replacing them is going to help stop the leaks. The majority of the oil is probably leaking out the rear intake cork seal. Best bet is to remvoe the intake, new gaskets, use RTV only, not the cork end seals. Spend a day on this and it'll be very rewarding!

I'll definitely get to the remedies you suggest. I know that's the only long term solution. But in the mean time I was hoping to use some gunk without hurting the engine. Glad to get your opinion.

67stang is right. These products are safe, but ineffective in your situation. About 4-5 hours with hand tools will replace the pan, valve cover and intake gaskets. The motor will run even better. I'd replace the oil pump while the pan is off, just for cheap insurance. A motor that sat for a long time may drop caked whatever into the pan, which could cause trouble. The Mustang has a removeable crossmemeber under the engine, making it very easy to pull and replace the pan gasket.
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