C1 3837223 Thermostat Housing

[Dennis G.]

I am posting two pictures of thermostat housings. They are both # 3837223. One has the 3837223 number on the drivers side with GM 1 on the other side. The other has the 3837223 number on the passenger side and GM 2 on the other side. My guess is these are first and second designs. The Judging Manual says the 1958 thermostat housings don't have the indentations in the housing so in that respect they are both correct. The car they are going on is an early (serial #934) 245 hp car.
Is one more correct then the other?

[Jack H.]

Re: C1 3837223 Thermostat Housing

My hunch is the GM1 and GM2 designations simply point to the physical line/mold that made the original part (a form of source traceablity). In terms of one being 'better' or 'more original' than another, that'll probably depend on the specific knowledge/belief of the particular NCRS judge(s) you draw...

[Roy B.]

Re: C1 3837223 Thermostat Housing

GM used more then one supplier , the difference is the company that made them ,it was a way for GM to know which company made one. There both NCRS correct in my opinion. It's like a logo mark!

[Michael K.]

Re: C1 3837223 Thermostat Housing

Dennis, are both of these housings aluminum? The one on right doesn't look like the material on the left which is obviously alum. as it should be.
Mike

[Jack H.]

Re: C1 3837223 Thermostat Housing

Methinks both are aluminum with one having been lightly media blasted while the other is relatively untouched, oxidized, and soiled...

[Dennis G.]

Re: C1 3837223 Thermostat Housing

Both of them are aluminum. The one that is dull (GM 2) is actually in the best shape with less corrosion on the neck, more of the seam, etc. So I'll probably use that one based on the feedback received. I appreciate the information fellow NCRS members pass on. It makes this hobby easier and more fun. So thanks to all.

[Christopher R.]

Re: C1 3837223 Thermostat Housing

Do some more researching. I believe there was a "Restorer" article on these. Or, much Tech Board discussion. If I remember correctly (and I probably don't) there were a few variations of this neck. Much discussion, but some were for early cars, some were late, some were service replacements, some for other Chevies.