Exhaust flange gasket between manifold and cat?

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This is the manifolds to the head.
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This is the manifolds to crossover pipe and crossover pipe to the cat on the 3.4l.
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It's the crossover pipe to the cat that I am working with. I bolted it all up with those two gaskets and it is leaking. I guess I will pull it all apart again and see what I can do. PITA studs and nuts on that crossover pipe.
 
Is there a trick to making this seal?

Cali. and federal are different. What year are you?

Aftermarket parts can mess things up. I have seen aftermarket gaskets that are too thin. Sometimes stacking two will work. Sometimes parts don't mate correctly and compress the gasket, so you need to do a little artistic grinding somewhere.
 
Cali. and federal are different. What year are you?

Aftermarket parts can mess things up. I have seen aftermarket gaskets that are too thin. Sometimes stacking two will work. Sometimes parts don't mate correctly and compress the gasket, so you need to do a little artistic grinding somewhere.

It's a 1998. One of them seams to be sealing but the other is loose no matter how much I tighten the nuts. Is stacking two on that one port ok? I might as well stack both I guess.
 
It's a 1998. One of them seams to be sealing but the other is loose no matter how much I tighten the nuts. Is stacking two on that one port ok? I might as well stack both I guess.

Honestly, do it whichever way allows you to get both tight. Whatever it takes...

I'd try two on both, first...
 
Without any gasket those two should fit all but flange to flange. The side the gaskets go on should fit into the holes on the other flange. If they don't look for the lip the gaskets go onto being bent. Or rust blocking the hole


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What kind of gasket is this? Should it be two rings? How the heck do you install them and get this to work without leaking? HALP!
I recently had to double up on a rear cali cat to muffler flange gasket. My old cat flange is a little bent making a cup to the flat muffler flange, not a tight fit. So I just put in 2 gaskets and some RTV. Couple months in, no issues.
 
Thank you kindly. I will take your advice tomorrow and I will take some pics.

I am going to be very liberal with the red rtv stuff too.

Make sure you clean ALL the old gasket material off both flanges. Also, as the durk said, the AM part is substandard to the OEM part. I just went through this and replaced all mine on my exhaust system accept for one (between the muffler and TP which was AM anyways) with OEM. I really had to chip and wire wheel a lot to get all the gasket material off of the 3 flanges I was working with (I'm CALI emissions though)
 

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