I bought a 67 Skylark without a motor or transmission that had one of these installed. I was unaware of it, and proceeded to install a 455 and TH 400 with a station wagon 3.23 rear end. I drove it for a week locally listening to every sound with the radio off, but it was set around 80 MPH. When I finally took it for its first shake down on the highway, I almost jumped out the window when it went off. I had no idea these were even made, let alone still working in my car after all that neglect and weather. I just turned it all the way to the right, and it was never heard from again!