Can anyone help give me an idea what rpm I,m running in what gear. I have no tach as of yet and I,m afraid of running to low or high. My truck is a 91 std. cab 4x4 with the intercooled turbo and 4. 10 gears. It also has the original Michilins on it. If I could get an idea what speed I should be shifting at it would really help Thanks tachless