Poston Style Header Question

[SteveZ82]

My driver side exhaust manifold was cracked pretty bad so I had an annoying exhaust leak. I ordered a replacement Poston style from oldbuickparts.com and they shipped it to me without a gasket. I got it put on with some RTV and the thing leaks like a sieve now. So bad it's kind of embarrassing. It's definitely coming from the head. Anyway, need to fix that as I lost some noticeable power. Looking to see what gasket I should use as the vendor hasn't got back to me on the type they ship with their full exhaust kit. Standard fel-pro OK? And yes, we checked the header...it was flat. Or should I just repair the stock one?

 

[Buick Mark]

Use a gasket

 

[SteveZ82]

Use a gasket

Thinking this guy.

https://catalog.remflex.com/ProductDetails.asp?ProductCode=13-002&CartID=1

 

[Hahny]

Use a gasket

X2

 

[Hahny]

I used fel-pro 1400 gaskets when I had my engine out last year and I'm running Poston headers and I have had zero leaks so far. The key is to make sure the two surfaces are flat.

 

[SteveZ82]

I used fel-pro 1400 gaskets when I had my engine out last year and I'm running Poston headers and I have had zero leaks so far. The key is to make sure the two surfaces are flat.

Thanks. We did make sure they are flat and they are. Used some etc to seal it but it didn’t work. I’m sure a gasket will help here. Car sounds like shit right now.


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[Hahny]

Thanks. We did make sure they are flat and they are. Used some etc to seal it but it didn’t work. I’m sure a gasket will help here. Car sounds like shit right now.


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Try a set of the 1400's out and report back to us later with your results. Good luck!

 

[SteveZ82]

Try a set of the 1400's out and report back to us later with your results. Good luck!

Will do. Ordered the set from summit. Thanks all.


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[GNVYUS 1]

I've always used RJC header gaskets on my Postons with no issues. I'm not a fan of just sealant on headers personally due to the possible labor hassle from leaks.

 

[captndave737]

I had Poston headers where the flanges were so out of plane no gasket would fix it. I brought them to a custom exhaust shop where they had a 48" belt sander. Put them on that and then a gasket and they didn't leak until they cracked, which they did a few times.

 

[SteveZ82]

I had Poston headers where the flanges were so out of plane no gasket would fix it. I brought them to a custom exhaust shop where they had a 48" belt sander. Put them on that and then a gasket and they didn't leak until they cracked, which they did a few times.

Hopefully that's not the case. We thought we checked good enough and it looked fine I got this header from TA Performance so it's not a Poston but the latest stainless header that's available.

 

[Hahny]

Hopefully that's not the case. We thought we checked good enough and it looked fine I got this header from TA Performance so it's not a Poston but the latest stainless header that's available.

TA makes a nice set of stock headers, you'll be fine.

 

[Hahny]

I had Poston headers where the flanges were so out of plane no gasket would fix it. I brought them to a custom exhaust shop where they had a 48" belt sander. Put them on that and then a gasket and they didn't leak until they cracked, which they did a few times.

 

[SteveZ82]

Just to update. Added the gasket today, world of difference. Now I have a small leak at the flange. The ball isn't seating right. Any tricks? We had everything loose and it just won't cooperate. It's not terrible but you can feel it at the left side of the flange. Was thinking I can just patch it with some quick steel or should I look at getting a new X over?

That was the last big job I had to do. 99% there.

 

[CenTexT-Type]

DId you put on a new flange seal? I used the Felpro from Rock Auto and mine sealed with not leaks. Also wrenched the >>> out of it too.

 

[SteveZ82]

DId you put on a new flange seal? I used the Felpro from Rock Auto and mine sealed with not leaks. Also wrenched the >>> out of it too.

We did not since it didn’t have it before. That’s not a bad idea instead of buying the two piece crossover.


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[CenTexT-Type]

Mine didn’t have a seal originally either, but the TA header seemed loose on my crossover so I gave it a shot. Sealed up nicely, Hopefully that will take care of your leak.