351 Cleveland 2V Coolant System Noise

I have a 72 MACH I with the 351 Cleveland. I rebuilt the engine sometime ago, but its been running fine. No over heating, no high coolant temps, just a boiling inside of the engine/hoses while running and after shutdown until it cools, then the noise goes away. 

I have:

1. Removed the Thermostat and it still does it.

2. Pressure tested the cooling system with 15 - 20 PSI with no leakage.

3. Played musical thermostat with many different ones, including one that was suppose to be the correct one for the 351. (Recommendations Welcome on others)

4. Restricter in the manifold is in place.

5. Put the car on ramps to try and purge trapped air as some have stated.

5. Tried cussing at it, with no results.

I've read some info on this problem, but have never seen a solution to it.

History: As you can see in my thread post; https://www.7173mustangs.com/thread-1972-mach-i-351c-2v-fmx-trans?highlight=1972+MACH+I

This car never did this in the past (1978-1987) or after an engine rebuild in early 80. 

Current overhaul has been in the car and on the road almost a year now.

Any ideas out there in Mustang land. 

Thank you for your time in assisting. Someone out there has surely ran into this problem in the past.

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libram, TommyK, and clevelandcoupe, thank you for the quick replies.

I have been keeping an eye on the coolant and oil looking for signs of one or the other in each. So far no evidence of either.

Head Gaskets on backwards?

I would like to think I did not make that mistake when I put the engine together, but since it was actually 2002 since I built it, as you can see from my orignal thread:

https://www.7173mustangs.com/thread-1972-mach-i-351c-2v-fmx-trans?page=2&highlight=1972+MACH+I

As you can see from my 2002 engine rebuild photos, assembly led me to oil priming the engine and turning it by hand for about 10 years, and I only started driving it in late 2016 or 17, so needless to say I don't remember much about it now.

One question on that; I understand from reading online in the past, there are tabs on the head gaskets that are suppose to be forward, but if there not, they are on backwards. I went to a friends auto machine shop and pulled an old used gasket and saw tabs that would be pointing outboard from each side when installed.

Now without looking at a head and block assembly is it possible to reverse them without an obvious error being made. I'm normally pretty good about checking and rechecking, but this was and still is the first 351C I have ever built. Other than that, some SB & BB Chevys and miscellaneous others.

Questions

1. Are the tabs a true sign?

2. If installed backwards, what causes this to happen without other standard problems associated with head gaskets?

I have another 351C in my shed, so I'll dig it out and compare with a set of FelPro gaskets like I put on the problem engine.

Thanks for the help guys,

Bluesky's

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I  have a pop up from the sight that keeps blocking my view.

Been trying to get done for 30 minutes now.

You can see from the block photo, the 2 large water ports are forward on the block.

The photo of the heads show them in their proper installed position.

There was a gasket still on the block on the right bank as seen in the photo.

Question 1: do the gaskets go on where both ports are open? 

Seems so, and that would have been how i most likely installed them.

Hope the photos help your thoughts on this problem.





https://ibb.co/dK0Rkc





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https://imgbb.com/upload image from mobile

 

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