dragrcr97, I like the Hurst line lock you show in the pictures. The installation looks very clean. This is much cleaner than running lines up and down the firewall to plumb in the line lock. Other than the messy look, there are too many joints and connections to possibly leak.

I think safety at the starting line area is the reason for the NHRA rule, and the manufactures installation instructions have to do with safety and function. They don’t want some one hurt, but they also want the valve to perform correctly.

I am still working on a practical plan, and still retain the differential pressure switch. I am also going to figure out

Bluecuda413, thanks for doing some research on why the switch is there. I am still working on a practical plan to simplify the plumbing and still retain the differential pressure switch. I have a couple of ideas that might work and keep the number of connections at a minimum. I will work on it this week end. If I come up with something, I will post a sketch.

I am also going to figure out the pressure change due to the movement of the spool. I need to get a replacement differential pressure switch, so I am going to stop into Inline Tube next week when I got to Detroit on business. I will either get the spool travel from them, or disassemble the new differential pressure switch and measure. I should be able to calculate the pressure change in the front system based on this information. This might be interesting information.

Thanks,

John