Ze Vette. H-Pipe flanges hit after changing out the motor mounts

So, I've gone at this a few different ways and I'm not sure why the front flanges of the H pipe are hitting. Exhaust is all stock front to back. The car's motor mounts were shot so I replaced with GM OEM mounts. At that point under hard throttle one of the front flanges started hitting the tunnel plate.

I've tried the following things.

1. I rechecked the motor mount fitment to make sure the tabs were aligned with the box. I also checked the torque on the mount bolts to make sure they were tight.
2. Changed out the mid-pipe spring hangers.
3. Moved the catback forward and backward to see if alterations to the position changed anything (shot in the dark).
4. Changed the muffler exhaust hanger isolators to eliminate any noises or movement from there.
4. Ground down some of the flange on the H-Pipe side to get more clearance. At this point the converter pipe flange would be the limiter.
5. Checked the exhaust manifold and converter pipe to see if there is any way to move them around and it appears there isn't either at the manifold or at the converter pipe.

Nothing seems to be helping the situation. I've got very little clearance between the flanges and the tunnel plate. Probably 1/4 inch or less. It would be nice to know what exactly is the correct amount of clearance so that I know whether there is a positioning problem with the exhaust.

Any suggestions would be appreciated. I want to stay completely stock because I autocross in a class that requires the car stay completely stock for most parts that might be suggested, such as aftermarket motor mounts. The most I can do with the exhaust is swap from the catalyst back.

Bump for the night crew. 

Were the motor mounts from the dealer or aftermarket OE parts.

Dealer. GM parts.

These are the factory manual diagrams of the system for reference. The parts hitting are the flanges on the far left side of this pic.

This is a closeup of one side showing how it bolts up to the cat pipe and how that bolts to the exhaust manifold.

With not much info, it looks like you should be able to rotate the clamps.  Can you find a better orientation to eliminate any contact?

Tried rotating the flange, still too close.

Can you find a "known good" z06 to compare against?

I have obtained a possible solution from one of the people on CorvetteForum, but I want to actually see whether it works before I report back. Sounds promising though.