Does anyone have any good photos of that OEM bracket that stabilizes this connection between the header pipe flange and the catalytic converter flange?

I notice that it was completely rusted off, and I'm wondering if that could have been one of the culprits that puts stress on the exhaust manifold studs for snapping off. If the exhaust is bouncing around day after day, I can only imagine those shocks are transferred directly to the exhaust manifold fasteners at the exhaust ports.

I need to fabricate a new one but need something as a guide to go from. If someone has any photos this would save me. Otherwise i'm going to have to go makeshift.

 

the bracket (or lack thereof) isn't the problem.
It's the motor mounts. With the motor slapping back and forth, the y-pipe moves in an awkward position, putting undue stress on the studs.
the studs simply fatigue over time from this stress, and snap.
the fix is to replace all of the studs with new ones, and replace the motor mounts with Nissan pieces (chinese rubber of other suppliers deteriorates faster, in my experience).

sorry to go off topic, but everyone seems to confuse these common problems with other problems.
I am sure the bracket you need is important, but it's not the cause of the problems.

 

Hopefully the filling of the OEM mounts with window weld will help me then. I left the OEM rubber, and then just filled the open parts, that way I still get some cusion.

Regarding your experience with the studs: I thought that the flex weave section on the header pipe, is precisely that, to flex. And the front studs I can't see being affected, yet they still all snap, as there is a strong pipe clamp that attaches to the tranny bellhousing. This keeps the front exhaust manifold from moving side to side or front to back, no matter what the mounts are doing-the engine and trans shift together. I can see the back studs being prone to what your saying though.

One concern without the bracket, is that a large amount of weight is now pulling on the rear exhaust manifold, as well as excessive shaking and vibration. The sagging of weight, I suspect could ruin the header pipe and the exhaust manifolds, as even the Cat is now being supported by that one clamp in the front, and both exhaust manifolds. The first hanger is quite far from the Cat, so this doesn't make things any better.

A strange symptom I had after 3 months of driving, is that the Header Pipe to Cat bolts sheared off, and they were brand new 8.8 bolts.

I was driving around like that for years without the bracket, because it rusted off (didn't even know it was there in the first place). The good news is I found out Walker makes them, so this is great, no need to make one.

I thank the suggestions on this forum and filled both motor mounts and both trans mounts with the window sealant. This site saved a ton of work down the road...possibly. We'll see. The new updated mounts are going in this week.