Configuration: AMC 401 (.030 over), slight cam, port matched heads, edelbroke intake, 454 TB, 16197427, $OE, BIN=BMHK, using TunerPro RT, and a Burn2

Right now my system has a standard 4Kohm knock sensor I bought at McParts (I don't remember the application but I have the part number on the receipt so I could find out) mounted to a grounded bracket behind my dash. I would like to hook up a knock sensor to my block so I can tune my timing a bit better. I have read that a knock sensor is "Tuned" to the block. What does that mean? Can I use any GM 4kOhm Knock sensor that will screw into my block? There is a coolant passage on the side of the block that I think will work. How do I pick the "correct'est" one?