What a difference. I had taken a steel worm clamp and fixed my EGT guage to the side of the manifold for several months. It mainly stayed around 400-600 degrees and was very slow in moving. We drilled and tapped the manaifold yesterday and what a difference. It is as responsive as my RPM guage. (up and down). With my Smarty set on 170HP simply driving down the interstate at 70mph I was reading a flat 1200 degrees.