sry im a newb to pretty much all of this but thx for telling me that one wont work. YEs my current block does rachet when i pull in and locks when going in the other direction, but does not grip the rope at all. My upper block is just a freewheeling harken.
I want a bottom block that clamps the line. What are my options? can anyone give me a link to a set up i can buy?

h17racer, where did you see the 6:1 main block? is that for both blocks, 70$?