How bad is the blown gasket?

I had a 92 Ford Tbird, really nice car, ran great, handled beautiful, I really liked the car, but it had a bad gasket, always having to fill up the water, couldnt drive far without it overheating.

Some guy told me about sodium silicate, I tried it, the car quit surging on idle, never had to add water, it ran beautiful and passed smog ever since.