Okay I think my lower thermostat housing may be cracked, not sure.
Here's the story though. My 74 Nova has the original 250 in it.
Prior owner put a used head on it. I ran the numbers while the valve cover was off. I think it came back as a 292 head.

Anyhow, I can see gray crap behind the lower thermostat housing and head also, where its bolted on. I guess they like permatex.

Mine has the ONE threaded hole on the drivers side.

The one that I can get has two threaded holes on the drivers side.

Will that matter? Like is it thicker with two holes and will hit somewhere? Like a pulley or something?

I have used or new lower therm housings in stock. Show a pic of the one you have.

Thanks Tom! I will take a photo tomorrow. I was going to call you. I seen the one you have with the two fittings on one side. Mine has one. I'll get a pic up tomorrow afternoon.

Okay heres some photos, you can see in a few there is strange crud around it, maybe an anti freeze slight leak.

And possible crack in the one photo.

I thought my first time buying parts from you would be custom parts. But...This cant wait I guess.


I had to replace the vavle cover gasket, and I ran the numbers, and the prior owner must have put a 292 head on the chevy 250 that I have. Don't know if that matters.

Head Number J69
1828000..I think



Single port on drivers side Maybe I just cap off a second port, if thats all you have?






Might Be Cracked??







Would a double hole one fit with my power steering bracket?

I would replace the gasket and clean up the surface, and look it over REALLY good. And see if you still have a issue.

I agree with Larry. Pull it off and clean it up. Probably just a bad gasket. I generally do not use a gasket. Either RTV Ultra Black or Ultra Gray.
Put a even 1/16 layer on it and bolt on lightly. Let sit for 20 minutes and tighten it down. The grey is the better stuff and sets up in 5 minutes.

I do have that exact used one if needed.

I’ll try that. The 5th photo up, the close up. Looked like it was cracked, but I couldn’t tell.

looks like a crack to me. watched a friend crack 3 of them in a week! to this day, I install both bolts, then snug both, then tighten evenly. I loosen in a similar manner.

I shoved my phone down there because my eyes aren’t sharp as they used to be. Looks like it was cracked and the PO try to slap a bunch of gray stuff on there.

Looks more like a casting line to me. Do you drive this daily? If not , pop it apart to fix it.

It isn’t driven daily right now. I’ll take it apart this weekend. If it is cracked I’ll give you a call and buy the one you have.
Hopefully it is a casting line.

I have a question. I have a sensor in that lower thermostat housing. And one on the side of my head also, about 6 inches away on the drivers side, same as the housing. What does each one do?? I know they must be both for a water temp??