If you want to pass tech inspection at the track the line loc needs to be installed after the valve (NHRA regulation 3:1)
Installation is simple:
1. Unscrew the two front brake lines from the proportioning valve and screw them into either side of a "T" fitting.
2. Put a plug in one of ports on the proportioning valve.
3. Run a new line from whichever hole you decided not to plug to the "IN" port on the line lock.
4. Run a new line from the "OUT" port on the line lock to the "Tee" fitting.
5. Plug any extra holes in the line lock.
6. Bleed brakes
7. wire your line lock