Where do I put the guage sensor?

You can use a Brass "T" and screw it in your manifold, letting the heater hose come off the "top", and the gage bulb out the side ( pointed to the rear of the engine). you will have to make sure when you mock it up, that the end of the bulb does not bottom out in the "T", you might have to modify it. You also might have to redrill the hole in the manifold. If you have a good ole fashioned hardware store near you, they shuold have all kinds of brass fittings available. If you play around with that it will work. Your other alternitive is to drill a new hole, for the new bulb. Keep in mind these are all "National Pipe Theads" so you have to use pipe thread taps. Using a variety of fittings I did this on both my cars. I'll see if i can post a pic, but i don't have any luck on this site. They are too large, sorry I can't help you with a pic.