The brake line lock was a product of the intense sport of drag racing. It allowed the forward brakes of a car to engage and lock independently of the rear brakes via a switch. When you talk about the brake line solenoid, you're referring to the entire unit itself-it's essentially an electric solenoid placed on the front brake line. If you have the need for one, this guide will help you pick one out.
Front or Rear
Because the system works naturally with the front brakes of your car, the first thing you have to consider is whether or not you car has front brakes, because most cars have rear brakes. While some brake line lock solenoids can be attached to the rear brakes, you will still need to have front brakes installed.
If you're an exclusively rear-brake car only, sad to say, you probably wouldn't want to make this purchase as all you will succeed in doing is getting your brakes locked to no appreciable effect! If you have brakes for both front and rear installed, then you're pretty much good to go!
The great thing about the solenoid itself is that it is universal fit. No need to find one that's exactly for your vehicle. What you do need to worry about is wiring. When you purchase one, make sure that it comes with two long wires attached to the top of the unit. These have to reach all the way back and up into the engine.
Some solenoids are, funnily enough, not sold with them and people assume that it can run by itself-this is never the case. Solenoids always require an external power source to drive it to action. If you come across those that claim to be self-powered, you have to be a little wary!