Welp, I purchased some stainless steel long tube headers and they fit pretty good. They are for a 2010-2012 Camaro 6.2-liter LS3. I got them because they looked like they tucked in pretty good and the collectors came out straight.
The passenger side fits snug. But I think I can get away with it.
The drivers side is great.
Both collectors dip a little low as you can see in the two pictures below. So I will need to cut those off and reposition them.
These next two pictures show the only modification I had to make. I used a flap disc to grind down the bottom of the frame only. I left the top alone. These pictures are viewing from the ground.
Drivers side:
Passenger side:
