Where to Mount Thermostatic Switch?

It looks like you’ll have to get creative and maybe put a “T” in the manifold.

I think some SBF thermostat housings have an extra threaded hole.

I noticed the Air Gap doesn’t have the water crossover in the back:



Like the regular Performer has:

If the intake route is out and your lookign for a clean look you can have someone tap into your radiator, or you could go a cheaper route like a inline setup. below is a shot of alumrad.com's unit, but im sure summit and others carry similar pieces.



This would replace a piece of your lower rad hose, it will require a ground wire, but both wires could be outta the way and likely unnoticable if mounted upside down.

I've done several using brass fittings to install a "T" from the local hardware supply store.