This kit does not come with a valve. You should be able to use existing valve on the truck and plumb it to the master using the 2 ports (1) 1/2-20 & (1) 9/16-18 on left side.
When using this kit you will not be using the mechanism in the bracket assembly as shipped. Remove it and use the pedal rod extension in the kit.
Firewall plate will not be used as it is designed for the lever mechanism and not the truck rod in this kit.