I'm sorry, I did not mean to get anyone twisted up by using the wrong term. Differntial Pressure Switch is what I meant.

I assume NHRA, and vendors for line-locks want the solenoid mounted after a differntial pressure switch to eliminate the possibility of an unsafe condition if trhere was a pressure drop within the differntial pressure switch when the brake pedal is released.

Functionally, if you want to use the line-lock to hold the car in position at the line against the rev-limiter, than any pressure drop is possibly going to let the car creep forward.

So that is why I was asking for examples of line-locks mounted down stream of the differntial pressure switch. Has anyone actually mounted a line-lock like this?

Thanks, John