[njsteve]

On the 72's the temp sender is a single terminal, button head, sender mounted on the driver's side cylinder head. This is a different location than was used on the 70 and 71 cars which had them mounted on the intake.

Here is a good thread on the exact temp sender unit you need and some tests I did on the repro units on page 2. Turned out that the $6 Wells #TU5 sender was the best, next to a vintage original sender. The current Delco replacements were completely inaccurate as were the LectricLimited units:

http://forums.maxperformanceinc.com/...ht=temp+sender

The three prong unit is the TCS sender that is on the pass side head. It is not designed or calibrated for the gauge and I doubt it will read correctly since it pretty much functions as a temperature-dependant on-off switch for the TCS system.

By the way, don't use teflon tape as it alters the ground resistance to the cylinder head from the sender.