I bought a complete tko 600 setup and I am pretty sure that I may have got the wrong crossmember. I measured from the inside of one of the mounting tab to the other inside of the other tab and it was 30 1/4". The problem is that from the inside to inside of the frame where the crossmember mounts is around 28 7/8". I'm just making sure I am looking at this right before I bother Frank. Or if anybody can get me a measurement of their tko crossmember on their first gen camaro that would be great. Here are some pics.

http://i9.photobucket.com/albums/a91/fish451983/DSC01524.jpg

http://i9.photobucket.com/albums/a91/fish451983/DSC01525.jpg

The crossmember I used on my TKO600 conversion mounted up on top of the frame rails and not on the sides. Maybe I'm not understanding your fitment problem. To verifty, I suggest should measure from the mounting hole center to the other mount hole center in your frame and see if this matches the distance in between the holes in your new crossmember.

Is this for a small block or a big-block ? Big block engines are offset approximately 1" to the passenger side. The cross member is also, and the mounting holes should be 1" closer to one end.