# '70 Ram Air III manifold leak



## Ramjet (Feb 24, 2020)

I've got a stock '70 "Judge" and the exhaust manifolds leak where they attach to the head. Upon further investigation, I noticed that there are only (3) ea. bolts holding each side - it's no wonder they leak!

All the aftermarket manifolds have more bolts.

Does anyone know why I just have 3 bolts per side?

Thanks for your help!


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## PontiacJim (Dec 29, 2012)

Ramjet said:


> I've got a stock '70 "Judge" and the exhaust manifolds leak where they attach to the head. Upon further investigation, I noticed that there are only (3) ea. bolts holding each side - it's no wonder they leak!
> 
> All the aftermarket manifolds have more bolts.
> 
> ...


Because that's all the factory used. The design of the manifold did not allow for all the bolt attachments found on the typical log manifold.

They are hefty & stiff enough that they don't flex and will seal well with just the 3 bolts. But that does not mean they will not leak over time. The gasket can deteriorate and that's when the leak begins. If left to leak long term, the manifold can errode and you won't get a good sealing surface.


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## Ramjet (Feb 24, 2020)

PontiacJim said:


> Because that's all the factory used. The design of the manifold did not allow for all the bolt attachments found on the typical log manifold.
> 
> They are hefty & stiff enough that they don't flex and will seal well with just the 3 bolts. But that does not mean they will not leak over time. The gasket can deteriorate and that's when the leak begins. If left to leak long term, the manifold can errode and you won't get a good sealing surface.


Can I resurface the originals and which aftermarket manifold is recommended these days?


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## PontiacJim (Dec 29, 2012)

Ramjet said:


> Can I resurface the originals and which aftermarket manifold is recommended these days?


I don't see why you could not have them lightly surfaced and trued up at any engine builder that surfaces heads. Then use a good exhaust gasket.

The after market RA exhaust manifolds come in 2 outlet sizes, so if your head pipes are good and you want to use them, match the outlet ports to your exhaust. If you want to go slightly larger, you can get the exhaust having a larger outlet and then purchase the mandrel bent head pipes to match and tie into your existing exhaust or go new all the way back.

You want D-port manifolds, not the round port RA II, RAIV, or SD type.






Pontiac Ram Air Manifolds


Pair LH and RH Ram Air D-port manifolds (shown with gray ceramic coating) <P> Fits 68-72 GM a-body with d-port heads. Also fits 70 1/2 - 81 f-body. ***For those using cylinder without end bolt holes (i.e. #7K3, 7M5, etc) we have a fix that doesn't requ




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## Ramjet (Feb 24, 2020)

PontiacJim said:


> I don't see why you could not have them lightly surfaced and trued up at any engine builder that surfaces heads. Then use a good exhaust gasket.
> 
> The after market RA exhaust manifolds come in 2 outlet sizes, so if your head pipes are good and you want to use them, match the outlet ports to your exhaust. If you want to go slightly larger, you can get the exhaust having a larger outlet and then purchase the mandrel bent head pipes to match and tie into your existing exhaust or go new all the way back.
> 
> ...


I've had the Judge about 8 months and the previous owner had it for 47 years. He took very good care of the car and it is unrestored. To make a long story short - I detected a leak and changed the stock looking gasket with another FelPro MS9499SH thin steel gasket with no help and after removing the original gasket I noticed Copper Coat sealant had been sprayed on both sides. I then tried again and used a thicker gasket ( Mr. Gasket Co. #5921) which was better but I still have a slight leak.
Your advise sounds good - For originality, I'm going to remove the factory manifolds and have them resurfaced to the bare minimum and go back with the FelPro MS9499SH gasket.


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## Johnnygoat (May 24, 2021)

I have had mine for 36 years. I bought new ones and one side leaks. Old ones leaked and I tried many different gaskets I did have them machined but I think they made the center slightly shorter to pull the ends tight. Mine is leaking in the center. I may switch it to my old one. It’s the sound of the judge!


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