For those of you using the GM temperature sensor for your stand-alone setup on your AE86, our little adapter will help you with committing such an impure deed.

Turned from aluminum, this adapter installs in either your front upper water neck or rear water housing where an M16 x 1.5 sensor (ECT or "Start Up" Sensor) is usually fitted.

3/8" NPT Female to M16 Male Aluminum Adapter