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Discussion Starter · #1 ·
When porting exhaust side of the head what is used to "plug" thermactor opening? The thermactor bump near the valve is drilled open and at the back of the head the port is closed shut. Im aware that it needs to be massaged alot but ill have an opening just sittin there when i cut it down some wont i? Do i tack weld once shortened towards the end and then finish port? Also i need recommendations on a good set of exhaust gaskets. Thanks for the ongoing help with my build!
 

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A lot of experienced builders use plain old high temp silicone. Just pump it in there until it comes out of all the orifices.
 

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When porting exhaust side of the head what is used to "plug" thermactor opening? The thermactor bump near the valve is drilled open and at the back of the head the port is closed shut. Im aware that it needs to be massaged alot but ill have an opening just sittin there when i cut it down some wont i? Do i tack weld once shortened towards the end and then finish port? Also i need recommendations on a good set of exhaust gaskets. Thanks for the ongoing help with my build!
Unless you are involved in a build where every last 1/10 of a horsepower is critical, the cross-talk between exhaust ports via the primary Thermactor passage is negligible....if that.

If you simply must plug the Thermactor passages, then you may use Irontites or you may goop a bunch of silicone sealer in the primary passage which feeds the three exhaust ports.

Paul
 

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Unless you are involved in a build where every last 1/10 of a horsepower is critical, the cross-talk between exhaust ports via the primary Thermactor passage is negligible....if that.

If you simply must plug the Thermactor passages, then you may use Irontites or you may goop a bunch of silicone sealer in the primary passage which feeds the three exhaust ports.

Paul
X2...

I take a slightly different approach. Clean out the main passage with a long 7/16" drill bit and drive two pieces of 7/16" non threaded rod in from each end measuring to 8 and 11 inches. Its obvious with length goes in which end of the casting.

You can then fill the remaining thermactor holes in the ports with silicone.

At this point in time I am not convinced that it is necessary excepting a max effort type build.


:D
 

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Discussion Starter · #5 ·
sounds good then thats all i needed to know...i actually just wanted to fill the hole in the exhaust chamber so ill fill it with high temp silicone....thanks
 

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I follow scottys approach but I tap and put little threaded plugs into the holes and jam into the rod. then I can port the exh port roof smooth. I would not weld on cast

just for piece of mind I use loctite
 

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Unless it's a all out race motor I wouldn't worry about it, but then again if it is a all out race motor you wouldn't be using those heads anyways.
 
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