273 coolant drip right exhaust bolt hole

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rick1062

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Hi Folks,

This is my first post on this site and I am new to mopar in general. I have mechanical experience, but not mopar.

So, here is my question. I am working on a 1965 Barracuda with a 273 and auto trans (not sure which trans). I removed the exhaust manifolds to replace the gaskets. Also had a coolant leak at the thermostat housing and after repairing that I pressured the cooling system up to check for leaks. I was surprised to a slight drip coming from the right rear exhaust bolt hole. I see there is a freeze plug at the back of the head right near the threaded hole telling me that coolant is not far away. So, how big of a problem do I have here with that coolant leak with the exhaust bolt removed.

Second question: Should any of the exhaust manifold mounting bolts be studs rather than bolts. The right front one on my engine is a stud and all others are bolts.

Thanks a lot for your experienced advice.

Rick
 
The factory put studs in the head for the front and back exhaust manifold attaching points. Also, I believe all four of those location (two per head) are into the coolant jacket. You can use studs or bolts (your choice and depending on how original you are staying with the build) but you will need to put thread sealant of some type on the four bolts/studs in those locations.
 
Better to put studs in front and rear so if you need to remove the manifold or replace the gasket for any reason, you can do it without worrying about losing coolant.
 
Ok guys, got it. Thanks to all. This the answer I was hoping for but need confirmation.

Rick
 
Demon 408 said:
The factory put studs in the head for the front and back exhaust manifold attaching points. Also, I believe all four of those location (two per head) are into the coolant jacket.
Click to expand...

I actually blew one right out of the head one early spring just after getting the car out of storage. The threaded exhaust manifold holes in the end of the heads DO go into the water passage. The wall thickness there is also extremely thin so it's easy for them to get messed up. The threads on mine were gone so I installed stainless Heli-coils and studs with thread sealant then nuts on the outer-most holes only. Worked for me.

Not 100% sure but the outer holes may have used those funny conical washers with the nuts. I was working with headers, not manifolds, so it didn't apply.
 
It is pretty common for 273 heads to crack at that same location (into the coolant passage near the stud holes). So take a good look while you're in there.
 
rick1062 said:
Hi Folks,

This is my first post on this site and I am new to mopar in general. I have mechanical experience, but not mopar.

So, here is my question. I am working on a 1965 Barracuda with a 273 and auto trans (not sure which trans). I removed the exhaust manifolds to replace the gaskets. Also had a coolant leak at the thermostat housing and after repairing that I pressured the cooling system up to check for leaks. I was surprised to a slight drip coming from the right rear exhaust bolt hole. I see there is a freeze plug at the back of the head right near the threaded hole telling me that coolant is not far away. So, how big of a problem do I have here with that coolant leak with the exhaust bolt removed.

Second question: Should any of the exhaust manifold mounting bolts be studs rather than bolts. The right front one on my engine is a stud and all others are bolts.

Thanks a lot for your experienced advice.

Rick
Click to expand...


Welcome to FABO Rick. toolmanmike
 
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