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Discussion Starter · #1 ·
After pulling the stock manifolds off my 350 I noticed the exhaust gaskets were missing. Is there a valid reason for leaving the gaskets off.
 

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Machined Surfaces..??

After pulling the stock manifolds off my 350 I noticed the exhaust gaskets were missing. Is there a valid reason for leaving the gaskets off.
NO, not unless they machined the surfaces to match exactly, but I still can't imagine not installing a gasket... so you hadn't experianced any exhaust leaks around the manifold..??:confused0006:
 

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Discussion Starter · #3 ·
NO, not unless they machined the surfaces to match exactly, but I still can't imagine not installing a gasket... so you hadn't experianced any exhaust leaks around the manifold..??:confused0006:
No, no leaking that I could tell. Actually was quite surprised to find them missing. Didn't notice any machining but I'll take a second look. Even if machined you's still run gaskets, right?
 

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No, no leaking that I could tell. Actually was quite surprised to find them missing. Didn't notice any machining but I'll take a second look. Even if machined you's still run gaskets, right?
Yes , i wouldnt run without them :bowtieb:
 

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You Bet !!

No, no leaking that I could tell. Actually was quite surprised to find them missing. Didn't notice any machining but I'll take a second look. Even if machined you's still run gaskets, right?
Yes, absolutely
 

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Discussion Starter · #6 · (Edited)
Previous owner did a mild but nice build to the motor, maybe even pros forget something once in awhile.:wink:

I refer to the 'bonehead' posts in chit-chat
 

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Discussion Starter · #8 ·
Sanderson doesn't use gaskets on their headers. They claim to have a patented process, but I don't see any difference than a machined manifold surface.???? ....http://www.sandersonheaders.com/Patented-Leak-Free-Flange.html
I just used Permatex on mine and so far no leaks.
Funny you mentioned permatex. Is it possible that a permatex type sealer could have "burned off" over time? I did scrape something off, not much, but thought it was just residue. Oh well, it is what it is. new gaskets are going on regardless
 

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If the header flange is soft metal and the tubes do not protrude to the port side - a lot of guys run no gasket (especially drags where they are doing work after every pass) - eventually the flange burnishes to the cast iron. But the maintenace level is higher as you are constatntly torquing everything. I recommend gaskets first, permatex copper second and don't like the no gasket approach - ESPECIALLY WITH ALUM HEADS - (believe it or not I have seen it done and charged big $$$ for the weld, remill and retap - that surface is the hardest to mill of all three).

Edit to add: GM discovered on motor home and truck engines that a gasket allowed the manifold to warp faster - starting with the 366 truck they eliminated the gasket - soon even the 350 passenger was a gasket omit - when using NEW parts (as in at the Flint pland with nw castings). If you have a fresh surface on a stock cast iron manifold you can torque to spec with no issue and no gasket - however a re-install shows spec of less than .025 warpage - or will require remachine or gasket or sealant - permatex copper is the equiv - I added this because I re-read and saw where you stated MANIFOLD not header - if you are warped beyond spec a well equipped machine shop should be able to fix ya right up - I did a few of these for around 20 bucks each.
 

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Discussion Starter · #10 ·
If the header flange is soft metal and the tubes do not protrude to the port side - a lot of guys run no gasket (especially drags where they are doing work after every pass) - eventually the flange burnishes to the cast iron. But the maintenace level is higher as you are constatntly torquing everything. I recommend gaskets first, permatex copper second and don't like the no gasket approach - ESPECIALLY WITH ALUM HEADS - (believe it or not I have seen it done and charged big $$$ for the weld, remill and retap - that surface is the hardest to mill of all three).
Duly noted. Got some copper, and some blue, and some red, and some clear, etc etc. Gonna have to put them in a crayon box!
 
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