Hey Matt, good to see your name pop up. Keith is right. I just installed an electric line lock on my front brake lines. A line lock is a momentary solenoid valve that blocks the applied pressure to the front wheels from releasing. Then you do your burnout with the rear brakes free, the fronts holding you in place. The valve near my seat is a mechanical block that will also hold the appplied pressure, but to the rear wheels. I'll use it for a temporary parking brake since I'm using front disc brakes on the rear that have no parking brake unit. But I say temporary since once you apply the mechanical valve, in time it will release as the pressure on the rear brakes seeps back thru the valve. I'll only use it to hold the car if I'm doing any mechanicals that requre the car to run and set in neutral. Other wise it will always be parked in gear.
The front electric line lock is the gold solenoid to the drivers side of the master cylinder. It is plumbed after the master but before the proportioning valve. This way it holds the pressure in the one line after the master but before it splits in the prop valve to each front caliper.
MArk L