Originally Posted by Uncle Ben
OK....I won't but..........
You could try some cleaning products to loosen it and back flush it but that would be really good fortune if it worked. You could pop out a freeze plug and see how it looks. The build up usually happens at the rear half of the block where the coolant flow is the slowest. I do hope a plugged block isn't the problem but it does happen when the coolant isn't changed few years.
It happens that on F engine water jacket components, the only aluminum is the t-stat housing. The water pump housing on a stock F is cast iron, unlike the aluminum housing on 2F and up. For this reason, a muriatic acid soak/flush might be feasable, inexpensive and potentially efficacious.