There isn't really a set place to put it. Anywhere around thedistribution block is fine. The most important thing is that you are able to get to and turn thr valve when needed. What I did was drill two holes in the firewall just in front of the distribution block, and went to home depot to get some washers and 2 nuts with bolts that would fit. Then I put 2 or 3 washers in between the firewall and the proportioning valve. This lifted it off the firewall just enough that the valve could be easily turned. Then just hook up the brake lines. I have photos if you would like to see them. Feel free to PM me.