I received this for Christmas and installed this electric accelerator pedal on my 1949 Chevy pickup with a 350 engine (Edelbrock 1405). After installing it, I noticed that it had an open port that allowed the vacuum to exit. This messed up my air/fuel ratio, so I called Edelbrock Tech Support. They told me this is to protect the coil from overheating and everything should be fine. It didn't sound right, but that's how they designed it. I tried adjusting the A/F ratio but the unmeasured vacuum leak made it impossible. I tried for 3 weeks and finally gave up. I unplugged it, plugged the vacuum connector plug back in, and went back to the manual choke. Now it works great and the A/F ratio is exactly where it should be and stable. I threw the choke in a drawer and it stays there. I also have a 1968 Quadrajet GTO that has an electric throttle. It doesn't have an open vacuum port to prevent the choke coil from overheating and it works great with a constant A/F ratio. I don't know why Edelbrock left this vacuum port open, but it's a bad design in my opinion. Stick to the hand throttle!