Thermostat Housing
 

Are there any other brand of thermostat housings that will work on our Pontiacs?

Are you asking about the water neck the upper hose attaches to? If so there are aftermarket chrome ones.

Go look on the Ames site.

Four Seasons 84843 is a cast iron replacement available at Rock Auto and Amazon under $15 . I used one on my 68 build .

MRY 84843

I just bought one today. My factory one had hollowed out too much over time and the thermostat can blow up into it. I dont for sure know that it works yet, but it looks legit.

The chrome ones I’ve had always leak, but an original in good shape

Yes, what the upper hose attaches to. Something that's taller than a traditional 2.5" Pontiac. I've seen some on sbc/BBC that's a bit taller and the neck swivels. Can either the sbc/BBC interchange with Pontiac?

I think the bolt pattern is the same. But the stock radiator hose isn’t going to fit anymore. So you would have to get cute on that. You can buy a thermostat spacer that would raise up the factory housing.

Chrome water outlets are a waste of money!
Eventually the expansion and contraction cracks the chrome plating and when that extends into the gasket area they leak.

Chevy water outlets have a slightly different bolt spread.

My factory one has a sealing ring cast into the gasket surface. At the end of the day, the only way I was able to not have leaks was to use a bead of straight RTV (specifically Permatex water pump and thermostat housing RTV) without a gasket to seal the thing. Haven't had a drop. It's actually what the service manual recommends when re-installing the thermostat housing instead of a gasket. Every gasket I've tried ends up weeping or leaking.

Regarding the chrome T-stat housings... I have 2 in use on my cars now and 1 on a TA I had in the late 80s-late 90s and none of them leaked & definitely didnt crack the chrome plating. Old one was in use for 100k+ miles & 10+ years... current 2 are 10 & 15 years of use... no leaks no cracked chrome or signs of either issue starting to happen. The chrome ones use an Oring to seal, if it gets too flat or leaks, just replace with a now O ring for 10+ more years of use.

If the manifold has any pitting in that area that will contribute to leaks on chrome or factory housings, a thinned out bead of good RTV like ultra black/grey etc will prevent that.

I have the aluminum t-stat housing sold my Ames on my '66 and it hasn't given me any trouble. It uses a traditional style paper gasket, and I applied a very thin skim coat of Permatex RTV to both sides of the gasket, and it has been 100% bone dry. One thing I love about my current engine, even though it's kinda boring mechanically, is that it does not leak or seep any fluids anywhere. It is so nice to finally have a Pontiac engine that doesn't have a pool of coolant underneath the t-stat.

https://www.amesperf.com/parts/23926/

I always found the key to a leak free housing was lapping the bottom of the housing on a flat surface, and if you can, run a fine flat file over the intake surface. And of course don't over tighten and bend the ears.
Surprisingly a lot of brand new housings are not really that flat on the bottom.

I use an Aluminum housing from Autozone with a gasket. No leaks and looks oem on an aluminum intake. Never liked the chrome ones, they were always warped right out of the package and the crappy O ring they come with doesn't seal well.

You have to check the depth of the threads on aftermarket intakes, sometimes shorter bolts are needed.

Also, SBC does not fit.

Agreed.
 

I use a belt sander. I have yet to find one that didn't need a little attention.

Big difference
 

Compared to the crap being made today? I don't think you can compare.

I have bought a couple from Nitemare Performance. Very nicely made and zero fitment issues. Uses a standard thermostat gasket. No crappy O rings

Crap being made today?? I agree thats the case for some stuff but I doubt any given brand of chrome T stat housing has changed from the original design... I have the Mr Gasket/Holley chrome housings that are the same as what they make today based on new ones Ive seen & sold.

Even butler sells 2 versions of these chrome housings, one is the same Mr G I have in use on 2 cars with zero signs of the claims made above... Im sure some can & do leak and some are made cheaper than name brands, but there are also other variable like pitting or not flat intakes or reusing a flattened O-ring, the vast majority of them work great and they get good reviews on summit etc.

If they were as bad as some claim I doubt butler would sell them. Some brands have a normal gasket version too if thats preferred over the O-ring. Stock housings are fine too but some guys like to dress up the engine with non stock shiny parts.

I used the Rockauto one. Looks good, good quality I guess but it would not seal with just a blue Felpro gasket. I hit it with the belt sander then used a little gaskacinch and no leaks

Ive got a couple old chrome ones still in service that work fine. They are the o-ring style. That's the only chrome style I've ever tried and they've always sealed fine for me.
In fact I just bought a new one for the 598 because the chrome on my original that must have been 20 years old was showing some age. The new chrome o-ring housing sealed right up and has been working fine all summer.

Ive got some originals hanging on the wall that I use occasionally for dyno sessions, they seem to work fine with a quality gasket, just used one on a recent dyno. I use the thick felpro gaskets on them that compress nicely, not that cheap paper thin garbage, that would most likely have a leak. That's usually the first gasket the parts guy grabs unless you tell him you want the felpro. They are so used to customers wanting the cheapest thing it's become expected I guess.