Aftermarket coolant temperature gauge sensor for my 3V is located 3/4 way to the back of the block on the driver's side. I routed the sensor harness as far away from the American Racing Headers as I could minimum of 5" or so. Split loom covering is entirely burnt off or melted flat. Surprisingly the actual sensor wire covering looks unaffected by the heat.

What are you using with an ID of 1/4" or so to heat shield wiring?