Big block thermostat housings.

Fired up the 440 Sixpack for the first time in the 71 R/T Challenger.

All in all eveything went very well.
The carbs reminded me that you always need to check for leaks at the fuel lines, but that was a quick and easy fix.

Ran the engine, got the timing set and everything sounded great(especially with open headers)

Ran it for awhile to get some temp in it.
The engine has always ran very cool so it took awhile to get it warm, I thought I was in the clear with any leaks...then I noticed coolant weeping under the rear of the the housing.
Tried to tighten the bolts down but I don't think that will work.

It's the thick Milidon housing that some have had success with.
I used a new gasket with some Indian Head shellac for sealer...maybe that was my mistake.
I've NEVER had any luck with these POS aftermarket housings.

So I'm very happy with everything except the housing...I should have known better.
It sure was nice to DRIVE the car into the garage instead of pushing it like I've done for soo many years.

So time to drain the coolant and try again.
I'm not sure if I'm gonna try to seal it or go back to my tried and true stock housing.

Any suggestions?

I had one of those chrome versions and it leaked. I machined it flat on a belt sander and got it to seal for a little while and it leaked again. Best to throw the `chrome ones in the garbage. What worked for me:

- parts store iron water neck (or billet aluminum Mancini is supposed to be good)
- check for flatness and smooth if necessary. I touched up my new water neck on the belt sander
- install with a gasket and permatex #1... the hardening kind
- torque gently. too much torque will bend the housing and cause a leak

The iron water necks are inexpensive. With a coat of engine enamal they look fine. I have had zero problems for several years after doing the above.

I believe someone now making one with an o-ring seal.

I'm using this. Hasn't wept a drop since putting it on 7,000+ miles ago.
http://www.summitracing.com/parts/BSP-90820/

Yes, they are.
terrysautolab.com

It was in the Aug 2012 Mopar action.

I'm using a housing made by Billet Specialties on my 440 and have never had a leak. Part number is 90820. Very nice piece with the O ring it is an easy sealing housing.

bought a 440 source billet,works great.chrome is to hard to seal.

same BS here!!!

I got 2 of the newer Milidon chrome necks in use, neither one leaks, I've had some of the older necks, that were just junk, and a few with no issues over the years, I have an old CalCustom on my Challenger T/A...it's been on for about 30 yrs now!, and still looks good

...anyway, recently installed one (Milidon) in my kids Dodge truck, toss the gasket supplied, use a Duralast gasket (Autozone/parts store) PN# 35063 it's a lot thicker, install the gasket first using a film of Permatex Gold engine sealant under the gasket, after gasket install, add another film of Permatex Gold, then install the thermostat, then add the housing, tighten to spec evenly, should be ready to add coolant in about 1 hr...I've seen some guys put the thermostat down first then the gasket over it, that's an issue too,..plus that Indian head sealer some like to use is problematic as well, as well as form-a-gasket

Mike

I've always used the stock neck and never had an issue. Another case of If it's not broke don't fix it.

FWIW: When I first assembled my engine I too read all about leaky chrome housings. I stepped up and bought the Mancini piece. Never touched it again in 4 years.

Hard to seal anything against chrome.
Like RapidRobert says, a big O' file is your friend. I file old originals back to a nice flat, smooth surface. Removing chrome for a good seal is a must to me.

Didn't get mine from Summit, but I'm running an SS one on my 318.

http://www.summitracing.com/parts/PRS-1065/

I am using The Right Stuff instead of a gasket, works perfectly.
R.