My 327's water pump has a small hole (about like a match head) in it on the lower part of the main neck right where it turns into the main body. It's near the casting number. It sort of looks like it should be there but haven't noticed til now. What's its purpose? Thank you much.

It's called a weep hole. It allows coolant to escape if the seal fails.

In other words; If water is coming out of this hole, it is time for a new pump.

In other words; If water is coming out of this hole, it is time for a new pump.

or rebuild it yourself......its easy