New Tach please help!!!
Ok so I've got a new tach from AutoMeter. I have a question on how to read it. Imagine that the gauge lays out like this:
The question I have is how do you read the marks before the "1"?
The answer relates in a way to an issue I'm trying to figure out. I've got it hooked up to a 350 SBC that's all internally stock. I noticed that my truck idles at the "1" mark while cold and drops down to between the sixth and seventh mark once warmed up. Once this occurs, my truck begins to vibrate pretty bad and starts making a sound that as of now, no one i have spoken with can figure out what it is. What is the normal idle rpm for a 350 SBC motor?