Thermostat goose neck fitting question

[GoMangoBoys]

I have 2 different goose neck fittings.  One has a tapped hole for a fitting and the other does not.  What would that tapped hole be for and do I need it?
Thanks

[Filthy Filbert]

The one with the tapped hole is not factory.   At least, not of any of the muscle cars of the early 70s.   Maybe for something like an RV motor or a boat motor?    Could use it for anything you wanted.   aftermarket temperature gauge, an on/of fan switch for an electric fan controller, etc.

[Dakota]

I've used both.  Definitely stick with the factory one (on the left).   The other as, as noted above, is aftermarket.   It lacks the lip (or whatever you call it) that helps hold the hose in place.   There were a couple of reviews online for the aftermaket one of people having the hose pop off which would get exciting in a bad way.

I had originally tried the aftermarket one because I needed the extra tapped fitting for a water temperature senaor for my FiTech EFI. I think there are extra fittings on aftermarket intake manifolds but I'm using a stock one.   The aftermarket thermostat housing developed a crack (probably my fault) shortly after installation.   I came across the bad reviews right before I ordered a replacement, so I moved the temp sensor to one of the block drain plug locations instead.  The sensor is working fine in that location.

Unless you're running some aftermarket stuff like EFI or an extra temp gauge, I don't believe you'll need the extra tap.     

[MoparLeo]

The most durable would be the cast iron housing as the aluminum ones eventually get deep pitting from oxidation.

[GoMangoBoys]

@Dakota  The one on the left in my picture is the one that YOU gave to me.  If I understand your post correctly, it sounds like you should have kept it?

[Dakota]

  At the time, I didn't know what I didn't know.  Oh well.  At least it went to a good home!