Mark,
did you look at flipping them upside down so that the end is low not high?
My thought is that if I take the LS7 headers I have and use them for the head side flange and adapt the tube shape to the c8 headers. The C8 headers, now upside down, would exit low with a slight up angle, much like I have see builders make for the exhaust adapter for the LS7 headers.
I am positive that there will be hiccups and issues, there always are lol. But that’s the fun right?!?
Yep flipping them upside-down is what I was thinking. I never got my hands on a set so was just going off internet pics as well. After changing the flange, the area I thought was going to be the problem is that the C8 headers stick out to the sides quite a bit. There's not that much clearance between the header flange on an LS/LT block and the frame (about 5.75"). Depending on the angles of the pipes / bends maybe it could be possible. I'd say if you can get your hands on a set to play with, go for it and let us know
